JPH0378423B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to porous polymeric structures. More particularly, the present invention relates to microporous polymeric structures that are easy to manufacture and feature three-dimensional, cellular microstructures. Several very different techniques have previously been developed for producing microporous polymeric structures. This technique is known to those skilled in the art as classical phase inversion.
These range from what is called nuclear bombardment, to incorporation of microporous solid particles into a matrix and subsequent leaching, to sintering the microporous particles together in some manner. Conventional efforts in this field have involved other techniques as well as countless variations of what are considered classic or basic techniques. The importance of microporous polymeric products arises from the myriad possible applications for this type of material. The possible applications for this are well known and range from ink pads and the like to skin-like breathable sheets and filter media. Moreover, for all possible applications, commercial use has been relatively modest. And the commercially used technology has various limitations that do not allow the versatility necessary to expand this application to reach the possible market for microporous products. As mentioned above, some commercially available microporous polymer products are made by nuclear bombardment techniques. This technique allows a fairly narrow pore size distribution to be obtained; however, the pore volume must be relatively low to ensure that the polymer does not degrade during production (i.e.
void space of approximately 10% or less). Many polymers cannot be used in this technology due to the polymer's lack of ability to corrode. Still further, this technique requires that a relatively thin sheet or film of polymer be used, and the process is not carried out to avoid "double tracking," which results in the formation of oversized pores. Significant expertise must be used. Classical phase inversion has also been used commercially to form microporous polymers and certain other polymers from cellulose acetate. The classic phase inversion is REKesting's
SYNTHETIC POLYMERIC MEMBRANES,
Described in detail in McGraw-Hill, 1971.
In particular, on page 117 of this document it is clearly stated that classical phase inversion involves the use of at least three components: a polymer, a solvent for this polymer and a non-solvent for this polymer. . Reference may also be made to US Pat. No. 3,945,926, which teaches the formation of polycarbonate resin membranes from casting solutions containing resin, solvent, and swelling agents and/or non-solvents. In lines 42-47, column 15 of the said patent:
It is noted that in the complete absence of swelling agent, phase inversion does not normally occur and that at low concentrations of swelling agent, structures with closed cells result. From the above discussion, it is very clear that classical phase inversion requires the use of solvents for the system at room temperature, and thus many other useful polymers cannot be substituted for polymers such as cellulose acetate. . Also, from the standpoint of this process, this classical phase inversion method generally has to be extracted subsequently. Formation of the film is limited by the use of large amounts of solvent used in the preparation of the solution. It is also clear that classical phase inversion requires a relatively high degree of process control to obtain structures of the desired shape. Thus, the relative concentrations of solvent, nonsolvent, and swelling agent are as described in U.S. Pat.
− Must be adjusted critically as discussed in column 16. Conversely, in order to vary the number, size and homogeneity of the resulting structures, the aforementioned parameters must be varied by trial and error. Other commercially available microporous polymers are made by sintering microporous particles of polymers ranging from high density polyethylene to polyvinylidene fluoride. However, it is difficult with this technique to obtain products with the narrow pore size distribution required for many applications. Yet another common technique that has been the subject of significant prior attempts involves heating various liquids and polymers to form a dispersion or solution, followed by cooling and subsequent removal of the liquid, such as with a solvent. Methods of this type are described by way of example only and not in a comprehensive manner in the following US patents: No. 3607793; No. 3378507;
No. 3310505; No. 3748287; No. 3536796; No.
No. 3308073 and No. 3812224. The techniques described above do not appear to have been commercially utilized to a significant extent, if at all, perhaps due to the lack of economic viability of certain previously developed methods. Also, this conventional method does not allow the production of microporous polymers that typically combine desired pore sizes and pore size distributions with microcellular structures. With respect to microporous polymers obtained by the prior art, hitherto known methods are based on isotropic olefinic or Oxidized polymers could not be produced and thus could not exhibit a high degree of pore size uniformity throughout the sample. Some prior art olefinic or oxidized polymers have pore sizes within the above range, but without a relatively narrow pore size distribution, thus making this material difficult to use in applications such as filtration requiring a high degree of selectivity. make it less valuable. Furthermore, conventional microporous olefin-based or oxidized polymers, which are considered to have relatively narrow particle size size distributions, are outside the above range and are typically not suitable for use in applications such as ultrafiltration. has an absolute pore size with a substantially smaller pore size. Finally, some prior art olefinic polymers have pore sizes within the aforementioned range and what is considered to be a relatively narrow pore size distribution. However, this material is made through the use of techniques such as stretching which imparts a high degree of orientation to the resulting isotropic material, making this undesirable for many applications. Thus, about
There is a need for microporous olefinic and oxidized polymers having pore sizes in the range of 0.1 to about 5 microns and characterized by a relatively narrow isotropic pore size distribution. Also, a major drawback of many previously available microporous polymers is their low flow rates when used in structures such as microfiltration membranes. One of the primary reasons for this low flow rate is the typically low void volume of many of these polymers. Thus,
Perhaps 20% or less of the polymer structure is the "void" volume through which the filtrate flows, and the remaining 80% of the structure
is a polymeric resin that forms a microporous structure. Thus, and especially with respect to olefinic polymers,
A need exists for microporous polymers that have a high degree of void volume. The Castro and Stoll applications described above describe highly advantageous methods of converting certain types of liquid amine antistatic agents into materials that behave as solids. The advantages of the resulting processing are real and It would be equally beneficial to be able to convert other useful functional liquids, such as flame retardants, into materials that behave as solids. It is therefore an object of the present invention to produce microporous polymers characterized by narrow pore size. There is a product that is used. Other purposes are to provide an easy way to allow economic manufacturing of microscopic poles. Another purpose is to apply to very many useful thermoplastic polymorphisms. A related and more specific object is to provide a method for easily forming microporous polymers from polyolefins, condensation polymers, and oxidized polymers. Still another object of the present invention is to provide microporous polymers in structures ranging from thin films to relatively thick blocks.Another object is to provide microporous polymers in structures ranging from thin films to relatively thick blocks.Another object is to provide microporous polymers with structures ranging from thin films to relatively thick blocks.Another object is to provide microporous polymers with structures ranging from thin films to relatively thick blocks. Other objects and advantages of the invention will become apparent from the following discussion and the accompanying drawings.While the invention is susceptible to various modifications and alternative forms, preferred embodiments thereof are herein shown in detail. However, it should be understood that there is no intention to limit the invention to the particular forms described.
It is intended to cover all modifications and alternative forms within the spirit and scope of the invention as expressed in the claims. It is now possible to render any synthetic thermoplastic polymer microporous by first heating the polymer described above and a compatible liquid as discussed below at a temperature and time sufficient to form a homogeneous solution. There was found. The solution thus formed is then allowed to assume the desired shape and subsequently cooled in this shape to a rate and temperature sufficient to initiate thermodynamically non-equilibrium liquid-liquid phase separation. . Since the solution is cooled in the desired shape, no mixing or other shear forces are applied while the solution is undergoing cooling. This cooling is continued to form a solid. It is only necessary for this solid to obtain sufficient mechanical integrity to allow it to be handled without causing physical deterioration. Finally, at least a substantial portion of the compatible liquid is removed from the resulting solid to form the desired microporous polymer. Certain novel microporous olefinic and oxidized polymers of the present invention are characterized by:
Characterized by narrow pore size distribution. This narrow pore size distribution is explained in detail below by the sharpness function “S”.
It can be expressed analytically as The "S" values of the olefinic and oxidized polymers of this invention range from about 1 to about 10. The above-described polymers of the present invention are also characterized by average pore sizes ranging from about 0.10 to about 5 microns, with about 0.2 to about 1 micron being preferred. Furthermore, the microporous product is substantially isotropic and therefore has essentially the same cross-sectional shape when analyzed along any spatial plane. In another aspect of the invention, it is compatible with synthetic thermoplastic polymers, particularly polyolefins, ethylene-acrylic acid copolymers, polyphenylene oxide-polystyrene blends, or blends of one or more of the foregoing polymers. The method of making microporous polymers is carried out such that a mixture of soluble liquids is heated to a temperature and time sufficient to form a homogeneous solution. This solution is then cooled, thus forming multiple droplets of substantially the same size in substantially the same amount of time. This cooling is then continued to solidify the polymer and at least a substantial portion of the liquid is removed from the resulting solids to form the desired cellular polymer structure. The method described above produces cellular, three-dimensional, void microstructures, i.e. microporous cells characterized by a series of closed cells having a substantially spherical shape and pores or passageways that interconnect with adjacent cells. A combined product results. The cells are evenly spaced throughout three dimensions and the interconnecting pores have relatively narrow diameters with a size distribution as measured by mercury infiltration. For ease of reference, microporous polymers with such a structure are referred to as "cellular." A related aspect of the invention provides novel microporous polymeric products that behave as solids and contain relatively large amounts of functionally useful liquids, such as polymeric additives including flame retardants. In this way, the useful liquid gains the processing advantages of a solid material that can be used directly, for example as a masterbatch. This product can be produced either directly by using a functional liquid as a compatible liquid and without removal of this compatible liquid, or by reloading the microporous polymer after removal of the compatible liquid, or by reloading the functional liquid into a microporous polymer after removal of the compatible liquid. can be formed indirectly, either by displacing a compatible liquid before removal, such as by incorporating a Broadly, carrying out the process of the present invention involves heating the desired polymer with a suitable compatible liquid to form a homogeneous solution, cooling the solution in a suitable manner to form a solid material, and subsequently extraction of liquid to form a microporous material. Considerations involved in practicing the invention are described in detail below. Polymer Selection As noted above, the present invention surprisingly provides a technique for converting any synthetic thermoplastic polymer to microporous. Therefore, the method of the present invention is applicable to olefinic polymers, condensation polymers and oxidized polymers. Examples of useful non-acrylic polyolefins are low density polyethylene, high density polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene terpolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, poly(4- Methyl-pentene-1), polybutylene, polyvinylidene chloride, polyvinyl butyral, chlorinated polyethylene, ethylene-vinyl acetate copolymer, polyvinyl acetate, and polyvinyl alcohol. Useful acrylic polyolefins include polymethyl-methacrylate, polymethyl-acrylate,
Contains ethylene-acrylic acid copolymers and ethylene-acrylic acid metal salt copolymers. Polyphenylene oxide is an example of an oxidized polymer that can be used. Useful condensation polymers include polyethylene terephthalate, polybutylene terephthalate, nylon 6, nylon 11, nylon 13, nylon
66, including polycarbonate and polysulfone. Selection of Compatible Liquids It is thus necessary to first select the synthetic thermoplastic polymer that is to be rendered microporous in order to carry out the invention. Once a polymer is selected, the next step is the selection of appropriate compatible liquids and the relative amounts of polymer and liquid to be used. Of course, blends of one or more polymers can be used in embodiments of the present invention. Functionally, the polymer and liquid are heated with stirring to the temperature necessary to form a clear homogeneous solution. If a solution cannot be formed at any solution concentration, the liquid is unsuitable and cannot be used with the particular polymer. Because of selectivity, perfect prediction of the operability of a particular liquid with a particular polymer is not possible.
However, some useful general guidelines can be stated. Therefore, if the polymer involved is non-polar, non-polar liquids with similar solubility parameters at solution temperature are likely to be more useful. When this parameter is not available,
For general guidance furthermore readily available room temperature solubility parameters may be mentioned. Similarly, for polar polymers, polar organic liquids with similar solubility parameters should be investigated first. Also, the relative polarity or non-polarity of the liquid should be matched to the relative polarity or non-polarity of the polymer. Furthermore, for hydrophobic polymers, useful liquids typically have little or no water solubility. On the other hand, polymers that tend to be hydrophilic generally require liquids with some water solubility. Regarding suitable liquids, aliphatic and aromatic acids, aliphatic, aromatic and cyclic alcohols, aldehydes,
Certain types of organic compounds of various types are useful, including primary and secondary amines, aromatic and ethoxylated amines, diamines, amides, esters, and diesters, ethers, ketones, and various hydrocarbons and heterocycles. It has been found. However, it should be noted that this concept is highly selective. Thus, for example, not all saturated aliphatic acids are useful, and furthermore, not all liquids that are useful for high density polyethylene are necessarily useful for polystyrene, by way of example. As will be appreciated, useful ratios of polymer and liquid for any particular system can be readily developed from the values of the parameters subsequently discussed. It will be appreciated that if a blend of one or more polymers is used, the useful fluid typically must be operable with all of the polymers involved. However, it is possible for the polymer formulation to have properties such that the liquid does not need to be operable with all polymers used. As an example, the liquid used can operate with the main polymer or polymers if one or more polymer components are present in relatively small amounts that do not significantly affect the properties of the formulation. It must be. Also, while the most useful materials are liquids at ambient temperatures, materials that are solid at room temperature are Can be used. More particularly, solid materials can be used as long as phase separation occurs by liquid-solid separation and by liquid-liquid separation during the cooling process discussed below. The amount of liquid used generally varies from about 10 to about 90%. Any synthetic thermoplastic polymer can be used as long as the liquid selected as discussed herein forms a solution with the polymer and this concentration results in a continuous polymer phase upon separation during cooling, which is discussed below. will be discussed in detail. Some summaries of this system are useful to determine the range of polymer and liquid systems that can be manipulated. When forming microporous polymers from polypropylene, alcohols such as 2-benzylamino-1
-propanol and 3-phenyl-1-propanol; aldehydes such as salicylaldehyde,
Amides, such as N,N-diethyl-m-toluamide; Amines, such as N-hexyldiethanolamine, N-behenyldiethanolamine, N-coco-diethanolamine, benzylamine, N,
N-bis-β-hydroxyethylcyclohexylamine, diphenylamine and 1,12-diaminododecane; esters such as methyl benzoate, benzyl benzoate, phenyl salicylate, methyl silicylate and dibutyl phthalate; and ethers such as diphenyl ether, 4- Bromo-diphenyl ether and dibenzyl ether have been found to be useful. Additionally, halocarbons such as 1,1,2,2-tetrabromoethane and hydrocarbons such as trans-stilbene and other alkyl/aryl phosphatites are also useful, as are ketones such as methyl nonyl ketone. In forming microporous polymers from high density polyethylene, saturated aliphatic acids such as decanoic acid, primary saturated alcohols such as decyl alcohol, and
-dodecanol, secondary alcohols such as 2-undecanol and 6-undecanol, ethoxylated amines such as N-lauryldiethanolamine, aromatic amines such as N,N-diethylaniline, diesters such as dibutyl sebacate and dihexyl sebacate and ethers. , such as diphenyl ether and benzyl ether, have been found to be useful. Other useful liquids are halogenated compounds such as octabromodiphenyl, hexabromobenzene and hexabromocyclodecane, hydrocarbons such as 1-hexadecane,
diphenylmethane and naphthalene, aromatic compounds such as acetophenone and other organic compounds,
Examples include alkyl/aryl phosphatites, and quinolines and ketones such as methyl nonyl ketone. The following liquids have been found useful for forming microporous polymers from low density polyethylene: hexanoic acid, caprylic acid, decanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid and 6. Saturated aliphatic acids including stearic acid, unsaturated aliphatic acids including oleic acid and erucic acid, aromatic acids including benzoic acid, phenylstearic acid, polystearic acid and xylylbehenic acid;
Acids including branched carboxylic acids, tall oil acids, and rosin acids with an average chain length of 9 and 11 carbons, 1-octanol, nonyl alcohol, decyl alcohol, 1
- primary saturated alcohols including decanol, 1-dodecanol, tridecyl alcohol, cetyl alcohol and 1-heptadecanol, primary unsaturated alcohols including undecylenyl alcohol and oleyl alcohol, 2-octanol, 2-undecanol, di Secondary alcohols including nonyl carbinol and diundecyl carbinol, aromatic alcohols including 1-phenylethanol, 1-phenyl-1-pentanol, nonylphenol, phenylstearyl alcohol and 1-naphthol. Other useful hexyl-containing compounds are the polyoxyethylene ether of oleyl alcohol and about
Contains polypropylene glycol with a number average molecular weight of 400. Still further useful liquids are cyclic alcohols such as 4,t-butylcyclohexanol and menthol, aldehydes including salicylaldehyde, primary amines such as octylamine, tetradecylamine and hexadecylamine, secondary amines such as bis- (1-ethyl-3-methylpentyl)amine and ethoxylated amines including N-lauryldiethanolamine, N-talo-diethanolamine, N-stearyldiethanolamine and N-cocodiethanolamine. Another useful liquid is N-sec-butylaniline,
Dodecylaniline, N,N-dimethylaniline,
N,N-diethylaniline, P -toluidine, N
-ethyl-O-toluidine, diphenylamine,
and aromatic amines including aminodiphenylmethane, diamines including N-erucyl-1,3-propanediamine and 1,8-diamino-p-methane, other amines including branched tetramine and cyclododecylamine, cocoamide, Hydrogenated tallo-amide, octadecylamide, erucyamide, N,
Amides including N-diethyltoluamide and N-trimethylolpropanestearate, methyl caprylate, ethyl laurate, isopropyl myristylate, ethyl palmitate, isopropyl palmitate, methyl stearate, isobutyl stearate and tridecyl stearate saturated aliphatic esters including stearyl acrylate, unsaturated esters including butyl undecylenate and butyl oleate, alkoxy esters including butoxyethyl stearate and butoxyethyl oleate, vinyl phenyl stearate, isobutyl phenyl stearate, Aromatic esters including tridecyl phenyl stearate, methyl benzoate, ethyl benzoate, butyl benzoate, benzyl benzoate, phenyl laurate, phenyl salicylate, methyl salicylate and benzyl acetate and dimethyl phenyl distearate, diethyl phthalate, dibutyl phthalate , di-iso-octyl phthalate,
Di-capryl adipate, dibutyl sebacate,
Includes diesters including dihexyl sebacate, diisooctyl sebacate, dicapryl sebacate and dioctyl maleate. Still other useful liquids are polyethylene glycols including polyethylene glycols (having an average molecular weight of about 400), diphenyl stearate, polyhydroxylic esters (triglycerides) including castor oil, glycerol monostearate, glycerol monooleate, Glycerol distearate glycerol dioleate, glycerol monooleate, glycerol distearate glycerol dioleate and ethers including trimethylolpropane monophenyl stearate, diphenyl ether and benzyl ether, hexachlorocyclopentadiene, octabromobiphenyl, Halogenated compounds including decabromodiphenyl oxide and 4-bromodiphenyl ether, 1-nonene, 2-nonene, 2-undecene, 2-heptadecene, 2-nonadecene, 3-eicosene, 9-nonadecene, diphenylmethane, triphenyl Hydrocarbons, including methane and trans-stilbene, 2
-heptanone, methylnonylketone, 6-undecanone, methylundecylketone, 6-tridecanone, 8-pentadecanone, 11-pentadecanone, 2-heptadecanone, 8-heptadecanone,
Includes aliphatic ketones including methylheptadecyl ketone, dinonyl ketone and distearyl ketone, aromatic ketones including acetophenone and bendiphenone, and other ketones including xanthone. Still further useful liquids are tricylenyl phosphate,
Polysiloxane, Magette Hyacinth (product name)
(Ammerige Nebler), Terpine All Prime No. 1 (product name) (Givaudan-Delawante),
Bath oil Fragrance #5864K (trade name) (International Flavor and Fragrance Co., Ltd.), Fosclair P315C (trade name) (organophosphite), Fosclair P576 (trade name) (organophosphite), styrenated nonylphenol, Contains phosphorus compounds including quinoline and quinaridine. For forming microporous polymeric products in polystyrene, useful solutions include tris-halogenated propyl phosphates, aryl/alkyl phosphites, 1,1,2,2-tetrabromoethane, tribromoneopentyl alcohol. , 40% boranol CP3000 (trade name) polyol and 60% tribromoneopentyl alcohol, tris-β-chloroethyl phosphate, tris(1,3-dichloroisopropyl) phosphate, tri-(dichloropropyl) phosphate, dichlorobenzene and 1-dodecanol. In forming microporous polymers using polyvinyl chloride, useful liquids include methoxybenzyl alcohol, aromatic alcohols including 2-benzylamino-1-propanol, and 1,3-dichloro-
Contains other hydroxyl-containing liquids including 2-propanol. Still other useful liquids include halogenated compounds, including Firemaster T33P (tetrabromophthalic diester), and aromatic hydrocarbons, including trans-stilbene. Additionally, microporous products have been made from other polymers and copolymers and blends in accordance with the present invention. Thus, for forming microporous products from styrene-butadiene copolymers, useful liquids include decyl alcohol, N-tallow-diethanolamine, N-
Contains coco diethanolamine and diphenylamine. Liquids useful for forming microporous polymers from ethylene-acrylic acid copolymer salts include N-tallow-diethanolamine, N-cocodiethanolamine, dibutyl phthalate, and diphenyl ether. Microporous polymeric products using high impact polystyrene can be formed by using hexabromobiphenyl and alkyl/aryl phosphites as liquids. “Noryl”
For polyphenylene oxide-polystyrene blends (General Electric Company), microporous polymers are created by using N-cocodiethanolamine, N-talo-diethanolamine, diphenylamine, dibutyl phthalate, and hexabromophenol. . Microporous polymers are made from blends of low density polyethylene and chlorinated polyethylene by using 1-dodecanol, diphenyl ether and N-tallow-diethanolamine. Using 1-dodecanol as the liquid, a microporous polymer is made from the following formulation: polypropylene-chlorinated polyethylene,
High density polyethylene-chlorinated polyethylene, high density polyethylene-polyvinyl chloride and high density polyethylene and acrylonitrile-butadiene-styrene (ABS) terpolymers. To form a microporous product from polymethyl methacrylate,
1,4-butanediol and lauric acid have been found to be useful. ethylene carbonate,
Microporous nylon 11 is made using 1,2-propylene carbonate, or tetramethylene sulfone. Menthol can also be used from microporous products from polycarbonate. Selection of polymer and liquid concentrations Determination of the amount of liquid used is determined by the binodial and spinodal
An exemplary curve is shown in FIG. As shown there, Tm represents the maximum temperature of the binodial curve (i.e., the maximum temperature of the system at which binodal decomposition occurs), Tucs represents the upper critical solution temperature (i.e., the maximum temperature at which spinodal decomposition occurs), and φm at Tm where φc represents the critical concentration and φx represents the polymer concentration of the system required to obtain the unique microporous polymer structure of the present invention. Theoretically, φm
and φc should be substantially the same; however, as is known, due to the molecular weight distribution of commercially available polymers, φc is about 5% by weight greater than φm. To form the unique microporous polymers of this invention, the polymer concentration φx used in a particular system must be greater than φc. If this polymer concentration is less than φc, the phase separation that occurs as the system is cooled constitutes a continuous liquid phase with discontinuous polymer phases. On the other hand, using the correct polymer concentration ensures that the continuous phase formed upon cooling to the phase separation temperature is the polymer phase, which yields the unique microcellular structures of the present invention. It is necessary for Similarly, clearly the formation of a continuous polymer phase upon phase separation requires that a solution be formed first. When the process of the invention is not carried out and the dispersion is first formed, the resulting microporous product is similar to that obtained by sintering the polymer particles together. Therefore, it will be appreciated that the applicable polymer concentrations and the amount of liquid that can be used will vary with each system.
Suitable phase diagram curves for some systems have been previously disclosed. However, if a suitable curve is not available, this can easily be disclosed using known techniques. For example, a suitable technique is Smolders, Van Aartsen.
and Steenbergen
Kolloidz, u, z, Polymer, 243 , 14 (1971). A more general graph of temperature versus temperature for a hypothetical polymer-liquid system is shown in FIG. 1A. The portion of the curve from γ to α represents liquid-liquid phase separation in thermodynamic equilibrium. The α to β curve represents equilibrium liquid-solid phase separation, which would be recognized as a normal freezing point depression curve for a hypothetical liquid-polymer system. The upper shaded area represents upper liquid/liquid immiscibility that may exist in some systems. The dotted line represents the drop in crystallization temperature as a result of cooling at a rate sufficient to obtain thermodynamic non-equilibrium liquid-liquid phase separation. The crystallization plateau relative to the composition curve limits the usable composition range, which is a function of the cooling rate used, as discussed in further detail. Thus, for any given cooling rate, one can plot the crystallization temperature versus the percentage of resin or compatible liquid, and in this way obtain the desired microporous structure at a given cooling rate. The liquid/polymer concentration that produces the body can be determined. For crystalline polymers, determination of the usable concentration range by plotting the crystallization curves described above is a viable alternative to a phase diagram such as that shown in FIG. As an example of the foregoing, it may be shown in Figure 55, which is a plot of temperature versus polymer/liquid concentration showing melting curves at a heating rate of 16°C per minute and crystallization curves for polypropylene and quinoline over a wide concentration range. can. As can be seen regarding the crystallization curve,
At a cooling rate of 16°C per minute, the appropriate concentration range is approximately 20%.
of polypropylene to approximately 70% polypropylene. FIG. 56 is a graph of temperature versus polymer/liquid composition for polypropylene and N,N-bis(2-hydroxyethyl)talo-amine. The upper curve is a plot of the melting curve at a heating rate of 16°C per minute. The lower curve is a plot of the crystallization curves at cooling rates of 8°C, 16°C, 32°C and 64°C per minute in descending order. This curve shows two coincident phenomena that occur as the cooling rate increases. First, the flat part of the curve showing a relatively stable crystallization temperature over a wide concentration range decreases with increasing cooling rate, which means that as the cooling rate increases, the actual crystallization temperature decreases. Show that. The second observable phenomenon is the change in the slope of the crystallization curve that occurs with changes in the rate of cooling. Therefore, it appears that the flat portion of the crystallization curve increases as the cooling rate increases. Consequently, by increasing the rate of cooling, one can correspondingly increase the operable concentration range for forming the microporous structures of the invention and for carrying out the methods of the invention. can be estimated. From the foregoing, one need only prepare a small representative concentration of polymer/liquid and cool it at some desired rate to determine the operable concentration range for a given system. That is clear. After the crystallization temperature is plotted, the operable range of concentration becomes very clear. FIG. 57 is a graph of temperature versus polymer/liquid concentration for polypropylene and dioctyl phthalate. The upper curve represents the melting curve for the system over a range of concentrations and the lower curve represents the crystallization curve over the same concentration range.
A polypropylene/dioctyl phthalate system capable of forming a microporous structure is not expected, since this crystallization curve does not exhibit any flat portion where the crystallization temperature remains essentially constant for a range of concentrations; And in fact, this does not form. Reference is made to Figures 58 and 59 to appreciate the excellent correlation between the phase diagrams that determine the operable concentration ranges of polymers and liquids and the crystallization methods that make this determination. Figure 58 shows low molecular weight polyethylene and diphenyl ether polymers measured by conventional light scattering techniques using a thermally controlled vessel.
FIG. 3 is a state diagram for a liquid system. From the phase diagram in Figure 58, it can be seen that Tm is about 135°C and φm is about 7% polymer. Furthermore, it is clear that the cloud point curve intersects the freezing point depression curve at about 45% polymer concentration, thus from about 7% polymer to about
45% shows the operable concentration range of the polymer. The operable range determined from FIG.
From the crystallization curve which can be compared with the range that can be determined from Figure 59 which shows the melting curve for the same system at a heating rate of 8°C and 16°C/min and the crystallization curve for said system at a cooling rate of 8°C and 16°C/min. It can be seen that the substantially flat section ranges from slightly less than 10% polymer concentration to approximately 42-45% polymer depending on the cooling rate. Thus, the results obtained from the crystallization curves are in remarkable agreement with those obtained from the cloud point phase diagram. For amorphous polymers, reference may be made to a temperature versus concentration plot of the glass transition temperature as an alternative to a phase diagram such as that in FIG. Thus, FIG. 58 is a graph of temperature versus concentration versus glass transition temperature of low molecular weight polystyrene and 1-dodecanol supplied by Pennsylvania Industrial Chemical Company as Piccolastic D-125 at various concentration levels. . From Figure 58 it is clear that the glass transition temperature for polystyrene/1-dodecanol is essentially constant from about 8% polymer to about 50% polymer. It is therefore proposed that concentrations along a substantially flat portion of the glass transition temperature, analogous to the flat portion of the crystallization curve discussed above, are operable in the practice of this invention. It thus appears that a viable alternative method of determining the phase diagram for amorphous polymeric systems is to determine the glass transition curve and operate on a substantially flat portion of this curve. In all of the foregoing figures, crystallization temperatures were measured with a DSC-2, differential scanning calorimeter, or comparable equipment manufactured by PerkinElmer. Further, the effect of cooling rate in the practice of the present invention is discussed below. After selecting the desired synthetic thermoplastic polymer, compatible liquids, and potentially operable concentration ranges, it is necessary to select, for example, the actual concentrations of the polymers and liquids used. For example, in addition to considering the theoretically possible concentration range, other functional considerations must be made in determining the ratios to be used for a particular system. Thus, the strength properties produced must be taken into account as far as the maximum amount of liquid to be used is concerned. More particularly, the amount of liquid used should therefore allow the resulting microporous structure to have a sufficient minimum "handling strength" so as to avoid destruction of the microporous or cellular structure. On the other hand, the selection of the maximum amount of resin, the viscosity limits of the particular equipment used will dictate the maximum allowable polymer or resin content. Furthermore, the amount of polymer used should not be so great as to cause occlusion of cells or other areas of microporosity. The relative amounts of liquid used also depend to some extent on the desired pore size of the microporous material, such as the particular cell and pore size requirements for the final application involved. Thus, for example, average cell and pore sizes tend to increase slightly as liquid content increases. Regardless, for a particular polymer, the use of the liquid and its operative concentration can be readily determined by using the liquid experimentally as described. Of course the parameters discussed above should be followed. In fact, as will be appreciated, two or more formulations can be used; and the use of a particular formulation can be determined as described herein. Also, while certain formulations are useful, one or more of the liquids may be individually inappropriate. As will be appreciated, the particular amount of liquid used will often be dictated by the particular end-use application as well. Using high density polyethylene and N,N-bis(2-hydroxyethyl)talo-amine, by way of example of a particular embodiment, about 30 to about
Useful microporous products are produced by using 90% by weight of amine, preferably 30 to 70% by weight. For low density polyethylene and the same amine, the amount of liquid can usefully vary within the range of 20 to 90%, preferably 20 to 80%. In contrast, when diphenyl ether is used as a liquid, useful low density polyethylene systems have a
% liquid, with a maximum of about 60% being preferred. When 1-hexadecene is used with low density polyethylene, amounts up to about 90% or more can readily be used. When polypropylene is used with the aforementioned tallo-amine, the amine can suitably be used in an amount of about 10 to 90%;
A maximum amount of 85% or less is suitable. For polystyrene and 1-dodecanol, the concentration of alcohol varies from about 20 to 90%, with about 30 to about 70% being preferred. When a styrene-butadiene copolymer is used, the amine content is from about 20 to about 90%.
Covers a range of. When decanol and styrene-butadiene copolymer (i.e. -SBR) systems are used, the liquid content can suitably vary from about 40 to about 90%; for diphenylamine the liquid content varies from about 50 to about 80%. Suitable within range. When the microporous polymer is formed from an amine and an ethylene-acrylic acid copolymer, the liquid content varies within the range of about 30 to about 70%; for diphenyl ether, when dibutyl phthalate is used as the solvent. Similarly, they differ by about 10 to about 90%. Shaping of Homogeneous Liquids Following the formation of the solution, it is then processed into any desired shape or structure. Generally, and depending on the particular system involved, the thickness of the articles will vary from thin films of about 1 mil or less to relatively thick blocks of about 21/2 inches or more thick. The ability to form blocks thus allows the microporous material to be processed into desired complex shapes, for example by conventional extrusion, injection molding or other related techniques. Practical considerations involved in determining the range of thicknesses that can be made from a particular system include the rate of viscosity increase that the system undergoes as it cools. Generally, the higher the viscosity, the thicker the structure. The structure may therefore be of any thickness, as long as no coarse phase separation occurs, ie two distinguishable layers are visibly evident. It will be appreciated that if liquid-liquid phase separation is allowed to occur under thermodynamic equilibrium conditions, complete separation into two distinct layers will result. One layer consists of a molten polymer containing a soluble amount of liquid, and the liquid layer contains a soluble amount of polymer in the liquid. This state is shown in Figure 1 and 1A.
It is represented by the binodial line in the state diagram of the figure.
The limits on the dimensions of the objects that can be manufactured are governed by the heat transfer properties of the composition, because if the object is thick enough and the heat transfer is fairly poor, the cooling rate at the center of the object will be thermodynamically This is clearly because the phase separation is slow enough to reach a state of equilibrium and, as mentioned above, causes phase separation with distinct layers. Increased thickness is also obtained by adding small amounts of thixotropic material. For example, the addition of commercially available colloidal silica before cooling significantly increases the useful thickness, but does not adversely affect the distinctive microporous structure. The specific amount to be used can be easily determined. Cooling of Homogeneous Solutions As is clear from the above discussion, regardless of the type of processing (e.g., forming into a film, etc.), the solution must be cooled to form something that behaves and appears as a solid. The resulting material should have sufficient integrity so that it does not shatter during manual handling. Another test to ensure that the system has the desired structure is to use the solvent for the liquid used rather than for the polymer. If this material decomposes, the system used did not meet the required criteria. The cooling rate of the solution can be varied within a wide range. In fact, in normal cases, external cooling is not necessary and simply injecting a hot liquid system onto a metal surface heated to a temperature at which the film can be drawn off, for example, or alternatively onto a substrate at ambient conditions. It is satisfactory to form the film by forming blocks by injecting the film into the film. As discussed above, the rate of cooling must be fast enough so that liquid-liquid phase separation does not occur under thermodynamic equilibrium conditions. Furthermore, the rate of cooling has a substantial effect on the resulting microporous structure. For many polymer/liquid systems, if the rate of cooling is slow enough but still satisfies the above criteria, liquid-liquid phase separation will substantially reduce the formation of a large number of droplets of substantially the same size. Occur at the same time. If the cooling rate is such that a large number of droplets form, the resulting microporous polymer will have cellular microstructures as defined above, as long as all other conditions discussed above are met. Has a structure. In general, the unique structure of the microporous polymer of the present invention is obtained by cooling the liquid system to a temperature below the binodial curve, as shown in FIG. 1, to initiate liquid-liquid phase separation. It seems likely that In this state, a nucleus consisting essentially of pure solvent begins to form. When the rate of cooling is such that fine cell-like structures are produced, as each nucleus continues to grow it becomes surrounded by a polymer-rich zone that increases in thickness as the liquid empties. Seem. As a result, this polymer-rich area resembles a skin or film covering the growing droplet of solvent. As the polymer-rich zone continues to thicken, the diffusion of excess solvent through the skin decreases; and droplet growth correspondingly decreases, until finally this effectively ceases and the droplet reaches its maximum dimensions have been reached. In this respect the formation of new nuclei is more possible than the continuous growth of large droplets. However, to obtain this mode of growth, it is necessary that nucleation be initiated by spinodal rather than binodial decomposition. Cooling is thus carried out in such a manner as to form a plurality of droplets of substantially the same size in the continuous polymer phase at substantially the same time. If this decomposition method does not occur, no cell-like structures are generated. A suitable decomposition regime is generally obtained by using conditions that ensure that the system does not reach thermodynamic equilibrium at least until nucleation or droplet growth begins. Methodologically, this is accomplished by simply allowing the system to cool without applying any mixing or other shear forces to the system. The time parameter is also important when relatively thick blocks are being formed, in which case more rapid cooling is desirable. To the extent that cooling results in the formation of multiple droplets,
There is a general indication that the rate of cooling affects the size of the cells produced, with increasing rates of cooling producing smaller cells. In this context, approximately 8°C/
It has been observed that an increase in the cooling rate from 20 to 20 minutes clearly results in a reduction in cell size by half for polypropylene microporous polymers. Therefore, external cooling can be used, if desired, to adjust the final cell and pore dimensions, as discussed in further detail. The manner in which interconnecting passageways or pores are formed in cellular structures is not well understood. However, although applicants do not wish to be bound by any particular theory, there are a variety of possible mechanisms that may help explain this phenomenon, each of which is consistent with the concepts described herein. The formation of pores is therefore due to thermal contraction of the polymer phase upon cooling, and the liquid solvent droplets behave as incompressible spheres when the solvent has a smaller coefficient of expansion than the polymer. Separately, and as pointed out, even after the solvent droplets reach their maximum size, the polymer-rich phase still contains some solvent, and vice versa. As the system continues to cool, additional phase separation therefore occurs. The residual solvent in the polymer-rich skin therefore diffuses into the solvent droplet, reducing the volume of the polymer-rich skin and increasing the volume of the solvent droplet. Conceptually, this weakens the polymer skin; and the increased volume of solvent or liquid phase creates an internal pressure that can burst through the polymer skin and communicate adjacent solvent droplets. In connection with this last mechanism, the polymer redistributes itself into a more compact state as residual liquid is displaced from the polymer skin, for example by crystallization when such polymers are used. In this situation, the resulting polymer skin is prone to shrinkage and likely has defects or pores located in particularly weak areas. As expected, this weakest area is between adjacent droplets, and in this situation the pores form between adjacent droplets and create interconnections between the solvent droplets. Regardless of this mechanism, interconnecting holes or passageways are inherently created when the method is performed as described herein. Another explanation for the mechanism by which pores are formed is based on the “Marangoni effect,” which was developed by C. Marangoni (C.
Marangoni) Nuovo Cimento [2] 5-6.239
(1871: [3], 397193 (1878) and Marangoni. C., Ann. Phys Lpz (1871), 143337. The Marangoni effect is the spontaneous backflow of alcoholic beverages at the sides of the drinking glass ( reflux
off), particularly to explain the mechanism by which concentrated droplets flow back into the bulk of the liquid. The fluid in the droplet first penetrates into the fluid in the mass, and then some of the fluid quickly retreats back into the droplet. It is hypothesized that similar physical phenomena occur with respect to droplets formed as an effect of liquid-liquid phase separation. Thus, one droplet meets another, one fluid penetrates another,
The two droplets then rapidly separate, possibly leaving some of the liquid that then communicates the two droplets and forms the basis for the intercommunicating pores of the cellular structure. For a more recent discussion of this Marangoni effect, see Charles and Mason, J. Colloid Soc:, 15 , 236-267.
(1960). If cooling of a homogeneous solution occurs at a sufficiently fast rate, liquid-liquid phase separation will occur under non-equilibrium thermodynamic conditions, but the liquid-liquid phase separation will occur rapidly enough that essentially no nucleation and subsequent growth will occur. Solidification occurs. In such cases, there will be no formation of multiple droplets and the resulting microporous polymer will have no distinct cellular structure. Thus, under certain circumstances, different microporous structures can be obtained by using exceptionally high cooling rates. For example, when a solution of 75 parts of N,N-bis(2-hydroxyethyl)tallow-amine and 25 parts of polypropylene is cooled at different rates from about 5°C to about 1350°C per minute, the cellular structures are arise. The main effect of different cooling rates in the above range on the composition is the change in absolute cell size. about
When a cooling rate of 2000° C./min is carried out, the microstructures take on, for example, a fine lace-like, non-cellular appearance. When a solution of 60 parts of N,N-bis(2-hydroxyethyl)talo-amine and 40 parts of polypropylene is treated in the same manner, a temperature of 2000°C per minute is reached before a lacy non-cellular structure is obtained. A cooling rate of at least 100% must be achieved. In order to investigate the effect of cooling system speed on the cell dimensions of cellular structures and to investigate the rate of cooling required for the transition from the production of cellular structures to the production of structures with non-obvious cells, various Concentrations of polypropylene and N,N-bis(2-hydroxyethyl)talo-amine are prepared as a homogeneous solution. To conduct this investigation, the DSC-2 discussed above was used in conjunction with a standard X-ray machine and a scanning electron microscope. A thermal gradient bar was also used since the DSC-2 is capable of maximum cooling rates of approximately 80°C/min. The thermal gradient bar was a brass bar on which a sample could be placed and was capable of exhibiting a temperature difference of over 2000°C over a length of 1 meter. Using an infrared camera, first measure the temperature of the sample with a thermocouple and focus the camera on the dish placed closest to the 10 bar position to a temperature of 110 °C. It was measured. The camera emissivity control was then adjusted until the camera temperature reading matched the thermocouple reading. For any given run, the camera was focused at the location where the dish containing the sample solution cooled. The dish with the sample was then placed on the thermal gradient bar for 2 minutes. Once the dish was removed from the bar to be placed in the camera's field of view, the stopwatch was activated. As soon as the camera indicated that the dish had a temperature of 110°C, the stopwatch was stopped and the time was recorded. Thus, the determined cooling rate was based on the time required for the sample to cool over a temperature range of approximately 100°C. It has been found that the regulating limit with respect to the rate of cooling is not the amount of material cooled. It was noted that although heavier samples cooled more slowly than lighter ones, the silicone oil used at the bottom of the pan for thermal conductivity between the pan and the bar significantly affected the rate of cooling. Therefore, the highest cooling rate is obtained by placing the dish without silicone oil on an ice cube, and the slowest cooling rate is obtained with a dish with a heavy coating of silicone oil placed on a piece of paper. Ta. Five samples of polypropylene containing 80% of said amine were prepared from 0% of N,N-bis(2-hydroxyethyl)talo-amine for use in examining the effect of cooling rate on the resulting structures. did. 175 °C for samples containing 20% polypropylene, 230 °C for samples containing 40% polypropylene, 245 °C for samples containing 60% polypropylene, and 245 °C for samples containing 80% polypropylene. Approximately 5 mg of each of the above samples were heated in portions in a DSC-2 inside a sealed dish at 40°C to a holding temperature of 265°C for 100% polypropylene and 250°C for 100% polypropylene. Each sample was heated and held at the appropriate temperature for 5 minutes before cooling. After cooling the sample at the desired cooling rate, N,N-bis(2
-Hydroxyethyl)tallow-amine was extracted and the sample was analyzed. The results of the study are summarized in Table 1, which indicates the dimensions of the cells in microns in the resulting compositions. All cell dimensions were determined by taking measurements from each scanning electron micrograph.

[Table]

Table: Another cooling rate study was conducted using a sample of 20% polypropylene and 80% N,N-bis(2-hydroxyethyl)talo-amine on a thermal gradient bar. Five of these samples were cooled at various rates from a melting temperature of 210°C, and the results are summarized in Table 1, showing cell dimensions in microns, and followed the same steps as in the method used to obtain the data in Table 1. used.

[Front] Ami
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It is clear from Tables 1 and 2 that for increasing cooling rates, the cell size of the resulting composition generally decreases. Furthermore, for a polymer/liquid system consisting of 20% polypropylene and 80% N,N-bis(2-hydroxyethyl)talo-amine, cooling rates of about 1350 to 1700°C per minute change from essentially cellular to non-cellular. It is clear that the transition is complete in the nature of the resulting polymer into cellular form. This transition of the resulting structure corresponds to the fact that the polymer is substantially solidified after liquid-liquid phase separation has begun, but before the formation of multiple droplets as described above. Additionally 40% polypropylene and 60% N,N-
5 of bis(2-hydroxyethyl)tallow-amine
Samples were prepared and heated to 235°C according to the above steps.
From the melting temperature of 690°C per minute to 7000°C per minute
Cooled at a rate of . It was determined that for this concentration of polypropylene and the amine described above, the cellular to non-cellular transition occurs at approximately 2000° C. per minute. Finally, three samples of 20% polypropylene and 80% N,N-bis(2-hydroxyethyl)talo-amine were prepared to examine the crystallinity of the structures prepared over a range of cooling rates. and cooled at rates of 20°C, 1900°C and 6500°C per minute. From the DSC-2 data for this sample, 3
It was determined that the degree of crystallinity of the samples was essentially equivalent. It can therefore be seen that variations in the cooling rate have no significant effect on the degree of crystallinity of the resulting structure. However, it was determined that as the rate of cooling increased significantly, the results produced were less complete as expected. Removal of Liquid Forming a homogeneous solution of polymer and liquid and cooling the solution in a manner suitable to yield a material with suitable handling strength, then e.g. On the other hand, it is a non-solvent,
The liquid can be removed to form a microporous product by extraction with a suitable solvent for the liquid. The relative miscibility or solubility of the liquid in the solvent used determines its effectiveness, in part, with respect to the time required for extraction. Also, if desired, this extraction or leaching operation is carried out at elevated temperatures below the softening point of the polymer to reduce time requirements. Examples of useful solvents include isopropanol, methyl ethyl ketone, tetrahydrofuran, ethanol and heptane. The time required will vary depending on the liquid used, the temperature used and the degree of extraction required.
More particularly, in some cases, the liquid used in the system
It is unnecessary to extract 100% and small amounts are acceptable, depending on the requirements of the intended end-use application. The time required therefore varies anywhere from a few minutes to perhaps up to 24 hours or more, depending on many factors, including the thickness of the sample. Liquid removal may also be obtained by other known techniques. Examples of other useful removal techniques include evaporation, sublimation, and displacement. Furthermore, when using conventional liquid extraction techniques, the cellular microporous polymeric structures of the present invention exhibit a release of the liquid contained in the structure in a manner approaching zero order, i.e., the rate of release is likely to be high. It is noteworthy that after the initial period of , it remains essentially constant.
In other words, the rate of release is independent of the amount of liquid released; thus, for example, the rate at which liquid is extracted after three-quarters of the liquid has been removed from the structure is the same as when half of the structure is filled with liquid. It is roughly the same as when An example of this system showing an essentially constant release rate is the extraction of N,N-bis-(2-hydroxyethyl)tallow-amine from polypropylene with isopropanol as the extractant. Also, in either situation there will likely be an initial induction period before the rate of release can be ascertained. When liquid release can be driven by evaporation, the rate of release tends to be linear. Characterization of Microporous Polymeric Cellular Structures The microporosity that forms when cooling of a polymer/liquid solution occurs such that a large number of droplets form as described above and the liquid is removed therefrom. The product forms a cellular structure comprising a series of substantially uniform, closed microcells in micro-dimensions and substantially uniformly distributed throughout the structure. Adjacent cells interconnect by smaller pores or passageways. This basic structure can be seen from the micrographs in FIGS. 4 and 5. It should be appreciated that the individual cells are actually closed but appear open in the micrograph due to the disruption involved in the sample preparation for taking the micrograph. In the micro-dimensions, at least for crystalline polymers, this structure appears to have surfaces similar to fracture planes along the edges of crystal growth (see Figure 2), and in Figure 3. As you can see, it has a coral-like appearance. This cellular structure further resembles a zeolite clay structure, which contains distinct "chamber" and "entrance" areas. This cell corresponds to the larger chamber area of the zeolite structure, while the pore corresponds to the inlet area. Generally, in cellular structures, the average diameter of cells varies from about 1/2 to about 100 microns,
The present invention is about 1 to about 20 microns. On the other hand, the average diameter of the pores or interconnecting passageways is typically of a smaller dimension than the main body, for example, when the cell diameter of the microporous polymeric structures of the present invention is about 1 micron, the pores or The average diameter of the intercommunicating passageways is about 0.1 micron. As noted above, the cell diameter and also the diameter of the pores or passageways will depend on the particular polymer-liquid system involved, the rate of cooling and the relative amounts of polymer and liquid used. However, a wide range of cell to pore ratios is possible, such as from about 2:1 to about 200:1;
Typically the ratio is about 5:1 to about 40:1. As can be seen from the several figures, some of the exemplary cellular microporous polymer products do not have the unique microcellular structures described herein. However, it must be recognized that in some cases this structure may be masked by other modifications resulting from the particular liquid or polymer involved or the relative amounts used. This masking may be done in whole or in part.
They range from small polymer particles attached to the cell walls to coarse "leaf-shaped" polymer deposits, which tend to completely mask the underlying structures in micrographs. Thus, for example, and as can be seen in Figures 21 and 25, small polymer spheres are attached to the cell cavities of the structure. This redundant formation can be understood with respect to the nucleation and growth concepts described above. Therefore, in systems with very high solvent or liquid contents, the maximum cavity size is typically relatively large. This means that the time required for the cavity or droplet to reach its maximum size increases as well. During this time, extra nuclei can form nearby. The two or more nuclei then come into contact with each other before each reaches its maximum dimension. In this case, the resulting cellular structure has a lower integrity and a slightly lower regularity than the basic structure described above. Furthermore, even after the droplets have reached their maximum size, depending on the system involved, this solvent or liquid phase may still contain some residual polymer, or vice versa. In this situation,
As the system continues to cool, some additional residual phase separation occurs. When this residual polymer simply separates from the solution, polymer spheres can form as shown in FIGS. 21 and 25. On the other hand, if residual polymer diffuses into the polymer skin, this wall exhibits a hair-like and irregular appearance, thus providing a "leaf-shaped" structure. This "leaf" structure may mask only a portion of the basic structure, as seen in FIGS. 28 and 29, or it may mask the entire structure, as shown in FIG. This "leaf" structure is also more likely to occur with certain polymers. Accordingly, microporous low density polyethylene structures typically provide this type of structure, perhaps due to the solubility of the polyethylene in the particular liquid used. This can be observed from FIG. Moreover, when the level of liquid used is very high, this will also occur with polymers such as polypropylene that would otherwise present a basic structure.
This is because the basic structure of Figure 8 and the "leaf" structure of the microporous product of Figure 6 have a polymer content of 40% by weight compared to 10% polypropylene in the structure shown in Figure 6. This can be easily observed by comparing. For most applications, it is preferred to use a system that results in the formation of elementary cellular structures. The relative homogeneity and regularity of this structure provides predictable results as required for filtration applications. However, leaf structures are more desirable when relatively high surface area structures are desired, such as in ion exchange or various adsorption processes. As can also be observed, some of the structures have pores in the cell walls. This phenomenon can also be understood in terms of the concepts of nucleation and growth. Thus, in parts of the system where a few spatially connected droplets have already reached their maximum size, each droplet is sealed with a polymer-rich skin. However, in some cases, some solvent becomes trapped between the sealed droplets but cannot continue to migrate into the larger droplets due to the impermeability of the skin. Thus, in this case, a liquid nucleus forms and grows, resulting in a small cavity embedded adjacent to a large droplet. After extraction of the liquid, this smaller droplet appears as a pore. This can be observed in the microporous structures shown in Figures 11-12 and 20. Another interesting property of the cellular structure of the invention concerns the surface area of this structure. The theoretical surface area of a cellular microporous structure consisting of interconnected spherical cavities approximately 5 microns in diameter is approximately 2
-4 square meters/g. It has been found that microporous polymers made according to the present invention need not be limited to the theoretical limits of surface area. S.Brunauer, PHEmett and E.Telle
“The Adsorption of Gases in
Multimolecular Layers”J.Am.Chem.Soc., 60,
309-16 (1938), polypropylene and N,N-
For microporous polymers made from bis(2-hydroxyethyl)tallow-amine, the theoretical model surface area of the excess and no associated void space was determined as shown in Table 1. Table % Void Specific Surface Area 89.7 96.2 m ² /g 72.7 95.5 60.1 98.0 50.5 99.8 28.9 88.5Surface area can be reduced by careful annealing of the microporous polymer without affecting the basic structure.
Microporous polypropylene made with 75% void space using N,N-bis(2-hydroxyethyl)tallow-amine as the liquid component is extracted and dried at a temperature not exceeding room temperature, and subsequently the surface area heated to affect. The initial surface area was 96.9 m ² /g. After 11 40 minute heating times at 62° C., the surface area decreased to 66 m ² /g. Separately 66
Further heating at 60° C. for an hour reduced the surface area to 51.4 m ² /g. Treatment of another sample at 90° C. for 52 hours reduced the surface area from 96.9 to 33.7 m ² /g. When examined by electron micrograph, this microporous structure did not change much. These results are summarized in Table 1.

[Table] One of the unique features of the cellular structure of the present invention is the presence of both well-defined, substantially spherical, closed microcells uniformly distributed throughout the structure and well-defined pores interconnecting the cells. It is about existence;
It is very clear that this pore has a smaller diameter than the cell. Furthermore, the cells and interconnecting pores have essentially no spatial orientation and can be classified as isotropic. Thus, for example, there is no preferred direction for the flow of liquid through the structure. This is in sharp contrast to prior art materials which do not exhibit such cellular structures. Many prior art systems have featureless structures lacking definable structural shapes. It is therefore quite surprising that microporous structures can be created with such a degree of homogeneity, which is particularly desirable for many applications requiring highly homogeneous materials. This cellular structure can be defined in terms of the ratio of the average cell diameter ("C") to the pore diameter ("P"). Accordingly, C/P ratios as discussed above vary from about 2 to about 200, with about 5 to about 100 being typical, and about 5 to about 40 being more typical. This C/P ratio distinguishes the cellular structures of the present invention from any prior art microporous polymeric products. Since no prior art synthetic thermoplastic polymer structures with distinct cells and pores are known, all this prior art material must be considered to have a cell to pore ratio of 1. Another means of indicating the properties of the cellular structures of the present invention is by the sharpness factor "S".
This S-factor is determined by analyzing the mercury intrusion curve for a given structure. All mercury infiltration data discussed in this application was measured using a Micromeritics mercury infiltration porosimeter, model 910 series. This S value is defined as the ratio of the pressure at which 85% of mercury penetrates to the pressure at which 15% of mercury penetrates. This ratio is a direct indication of the variation in pore diameter over the center 70% of the pore in a given sample, which is equal to 176.8 divided by the pressure in psi. This S value is then the ratio of the diameter of the pore into which 15% of the mercury has entered to the diameter of the pore into which 85% of the mercury has entered. 1 to 15% and 85 to 100 of mercury intrusion
The range for % is ignored in determining the S-factor. Penetration in the range of 0 to 15% is ignored as this range is due to cracks introduced into the material as a result of the freeze-fracture the material underwent prior to the mercury infiltration investigation. Also, data in the 85 to 100% range is due to compaction of the sample rather than actual penetration of mercury into the pores, so this range is ignored. Typical of the narrow range of pore sizes exhibited by the compositions of the present invention, typical S values for this structure are approximately 1
and about 30, with about 2 to about 20 being typical, and about 2 to about 10 being more typical. The average size of the cells in the structure is about 1 to about 20
It is micron. As shown, cell size will vary depending on the particular resin and compatible liquid used, the polymer to liquid ratio, and the cooling rate used to form the particular microporous polymer. The same variables also have an effect on the average pore size of the resulting structure, which in the present invention ranges from about 0.05 to about 1
Microns, with about 0.1 to about 1 micron being particularly typical. Throughout this application, all references to cells and/or pore size, unless otherwise specified, refer to
It refers to the average diameter of this cell or pore in microns. By determining the above factors, cell size, pore size and S for the cellular microporous polymer of the invention, the cellular microporous polymer of the invention can be accurately defined. log of the cell-to-pore ratio (“logC/P”) and log of the ratio of the sharpness function S to the cell size.
There is a particularly useful means of defining a polymer in terms of ("logS/C"). Accordingly, the cellular microporous polymers of the present invention have a logC/P of about 0.2 to about 2.4 and a logS/C of about -1.4 to about 1.0; It has a logC/P of about 2.2 and a logS/C of about -0.6 to about 0.4. Non-cellular Structures The non-cellular structures of the present invention resulting from the cooling of a homogeneous solution at such a rate that the polymer substantially solidifies before the formation of a large number of droplets are primarily dependent on the actual pore size and spatial homogeneity of the structure. and the narrow pore size distribution of the material. In particular, this non-cellular microporous polymer is characterized by a sharpness function S, as described above with respect to cellular structures. S values exhibited by non-cellular structures range from about 1 to about 30, with about 1 to about 10 being preferred and about 6 to about 9 being more preferred. However, the pore size of the material is approximately
When ranging from 0.2 to about 1 micron, S
Values range from about 5 to about 10, and typically from about 5 to 10. This S value for olefinic and oxidized polymers with microporosity of this size is hitherto unknown, except for highly oriented, thin films made by stretching techniques. Thus, cross-sections of the polymer taken along the spatial plane exhibit essentially the same structural characteristics. The pore size of the non-cellular structures of the present invention is typically about
In the range of 0.05 to about 1 micron, about 0.1
to about 1 micron is typical, and about
0.2 to 1.0 micron is more typical. It is clear that a surprising feature of the present invention is the ability to produce isotropic microporous structures from olefinic and oxidized polymers, with porosity in the range of about 0.2 to about 1 micron and about
It has a sharpness value of 10. It is particularly surprising that this structure is made not only as a thin film, but also in the form of blocks and complex moldings. General When forming a film or block by injection onto a substrate such as a metal plate, the surface of the microporous polymeric structure of the invention in contact with the plate, for example, may have a non-cellular surface skin. include. Other surfaces, in contrast, are typically entirely open.
Skin thickness will vary slightly depending on the particular system as well as the particular process parameters used. however,
Typically, the thickness of the skin is approximately equal to the thickness of a single cell wall. Depending on the particular conditions, this skin can range from being completely impermeable to the passage of liquids to exhibiting some degree of liquid porosity. If a single cell-like structure is desired for the final application, this skin can be removed by any of several techniques. As an example, this skin is polished,
using any of several mechanical means such as puncturing the skin with a needle or breaking the skin by passing the film or other structure through rollers at different speeds. It can be removed by twisting. Alternatively, this skin could be removed by microtoming. This skin can also be removed by chemical means, ie, by brief contact with a suitable solvent for the polymer. For example, when a solution of polypropylene in N,N-bis(2-hydroxyethyl)tallow-amine is extruded as a thin film on an endless stainless steel belt conveyor, a small amount is deposited on the belt just before the solution application zone. The application of liquid solvent effectively removes the surface formed at the solution-steel interface.
Useful liquids are isoparaffinic hydrocarbons, materials such as decane, decalin, xylene, and mixtures such as xylene-isopropanol and decalin-isopropanol. However, for some end-use applications, the presence of skin is not only not harmful, but is a necessary ingredient. For example, as is known, ultrafiltration or other membrane-type applications use thin, liquid-impermeable films. Therefore, in this application, the microporous portion of the structure of the invention has particular use as a support for the surface skin, which is a functional membrane in this application. Whole cellular structures can also be produced directly by various techniques. Thus, for example, polymer-
The liquid system could be extruded into air or into a liquid medium such as hexane. As discussed above, the microporous polymeric structures of the present invention have cell and pore diameters with a very narrow size distribution indicating a unique structure and its relative homogeneity. The narrow size distribution of pore diameters is the 30th
As can be seen from Figure -33, this is clear from the mercury intrusion data. The structure is film (No. 30-32)
The same general distribution is obtained regardless of whether it is in the form of a block (Fig. 33) or a block (Fig. 33). The unique pore size distribution of the microporous structures of the present invention is described in detail in connection with the Examples, for example in US Pat.
This contrasts sharply with the significantly broader pore size distribution of conventional microporous polymer products obtained by the conventional processes described in 3310505 and 3378507. For any microporous polymer made in accordance with the present invention, the particular end-use application will typically determine the amount of void space and pore size requirements. For example, for prefilter applications, the pore size is typically 0.5 microns or greater, while for ultrafiltration, the pore size is about 0.1 micron or less. In applications where the microporous structure actually serves as a container for a functionally useful liquid, strength considerations dictate the amount of void space with controlled release of the contained functional liquid. It is specified. Similarly, in this case, the pore size is dictated by the desired rate of release, with smaller pore sizes providing slower rates of release. A minimum strength is generally desirable when the microporous structure is to be used to convert a liquid polymer additive, such as a flame retardant, into a solid; however, consistent with this minimum, the polymer It is typically desirable to use as much liquid as possible to serve as a container or carrier. Microporous Polymers Containing Functional Liquids From the foregoing discussion and consistent with one feature of the present invention, microporous polymers containing functionally useful liquids such as polymeric additives (e.g., flame retardants). An object is produced that behaves as a solid and can be processed. For this purpose, the resulting microporous polymer is reloaded with the desired functional liquid. This is done with conventional adsorption techniques, and the amount of liquid taken up is essentially the same as the amount of liquid used in forming the microporous polymer in the first case. Of course, any useful organic liquid can be used so long as the liquid is not a solvent for the polymer or will not attack or degrade the polymer at operating temperatures. Microporous products containing functionally useful liquids can be formed by using microporous polymers with either cellular or non-cellular structures as the matrix in which the liquid is incorporated. . Similarly, this microporous product can be produced by displacement techniques. According to this embodiment, a microporous polymeric intermediate is first prepared; and this liquid is then replaced with either the desired functionally useful liquid or an intermediate replacement liquid. In either case, rather than extracting the liquid used in forming the microporous polymeric intermediate, this displacement is accomplished by conventional pressure or direct air displacement or leaching techniques. Functional or intermediate recycling liquids can be used that can be used as extraction liquids to form microporous polymers, i.e. non-solvents for the polymers but with some solubility or miscibility in the liquids being replaced. has. Obviously, a small amount of the displaced liquid or liquids remains after displacement. End-use requirements typically dictate the degree of substitution desired; therefore, amounts of about 1 to about 10% by weight are acceptable in some applications. If desired, using liquids that can be easily removed by multiple displacement and/or evaporation allows removal of essentially all the liquid or liquids being replaced, i.e. about 0.03% by weight.
Less or more residual liquid is obtained. From an economic standpoint, it is generally desirable to use a replacement liquid that has a significantly different boiling point from the liquid being replaced so that it can be recovered and reused. For this reason,
It is desirable to use intermediate displacement liquids. As is also clear from the foregoing examples of useful polymer-liquid systems, another method of making polymer-functionally useful liquid materials is that many functionally useful liquids have a solid microporous structure. This includes the use of microporous polymeric intermediates without further processing, as it has been found that they can act as liquids that are compatible with certain polymers to form polymeric intermediates. Intermediates that behave as solids can therefore be used as lubricants, surfactants, slip agents, insect repellents, insecticides, plasticizers, pharmaceuticals, fuel additives, abrasives, stabilizers, insect and animal repellents, fragrances, Made directly with liquids useful as flame retardants, antioxidants, deodorants, antifoggants, and fragrances. For example, in low density polyethylene, lubricants can be lubricated by using either aliphatic or aromatic hydrocarbons with 8 or more carbon atoms or non-aromatic hydrocarbons with 9 or more carbon atoms. Or useful intermediates containing plasticizers are provided. Useful products containing surfactants and/or wetting agents are formed with low density polyethylene by using polyethoxylated aliphatic amines having 8 or more carbon atoms or nonionic surfactants. can. In polypropylene, the use of diethoxylated aliphatic amines having 8 or more carbon atoms provides a surfactant-containing intermediate. By using phenylmethylpolysiloxanes, polypropylene intermediates containing slip agents can be prepared, while by using aliphatic amides having 12 to 22 carbon atoms, low density polyethylene slip agent intermediates can be prepared. It is formed. Low density polyethylene fuel additive intermediates can be made by using aliphatic amines having 8 or more carbon atoms or aliphatic dimethyl tertiary amines having 12 or more carbon atoms. This tertiary amine also forms a useful additive intermediate with the methylpentene polymer. High density and low density polyethylene intermediates containing stabilizers can be formed by using alkylaryl phosphites. The use of glycerol mono- or diesters of long chain fatty acids having at least 10 carbon atoms provides a low density polyethylene intermediate containing an antifoggant. By using polyhalogenated aromatic hydrocarbons having at least 4 halogen atoms per molecule, flame retardant-loaded intermediates can be prepared in high-density and low-density polyethylene, polypropylene and polyphenylene oxide-polystyrene blends. . Of course, useful materials should be liquid at phase separation temperatures as described herein. Other systems found to be useful are identified with respect to the examples set forth below. Furthermore, polypropylene, high density polyethylene,
and low density polyethylene, certain types of ketones that have been found to be particularly useful as animal repellents can generally be used in the practice of this invention.
The ketones include saturated aliphatic ketones having 7 to 19 carbon atoms, unsaturated aliphatic ketones having 7 to 13 carbon atoms, 4-t-amylcyclohexanone and 4-t-butylcyclohexanone. The following examples are presented to more fully illustrate the invention, and are merely illustrative of the invention and are not intended to limit its scope. All parts and percentages are by weight unless otherwise specified. Method of Production The porous polymer intermediate and microporous polymer described in the following examples were produced by the following steps: A. Porous Polymer Intermediate Mixing the polymer and a compatible liquid, homogeneously Heating this mixture to a temperature, usually near or above the softening point of the resin, so that a solution is formed; and then cooling the solution without mixing or other shear forces to form a macroscopic solution. The porous polymer intermediate is formed by forming a solid homogeneous mass. When a solid block of intermediate is to be formed, this homogeneous solution can be given the desired shape by pouring it into a suitable container, usually made of metal or glass, and The solution is left to cool at ambient room temperature unless otherwise specified. Under room temperature conditions, the rate of cooling will vary depending on such factors as sample thickness and composition, but is typically within the range of about 10 to about 20 degrees Celsius per minute. The container is typically cylindrical in shape with a diameter of about 0.75 to about 2.5 inches and the solution is typically about 0.25 to about 2.5 inches in diameter.
Injected to a depth of approximately 2.0 inches. When the intermediate film is formed, this homogeneous solution is poured onto a metal plate heated to a temperature sufficient to allow drawing of the solution into a thin film.
The metal plate is then brought into contact with a dry ice bath to rapidly cool the film below its solidification temperature. B. Porous Polymers Microporous polymers are made by extracting the compatible liquid used to form a porous polymer intermediate, typically by repeatedly washing this intermediate with a solvent such as isopropanol or methyl ethyl ketone. form a polymer. EXAMPLES The following examples demonstrate some of the various polymer/compatible liquid formulations and prior art or commercially available microporous products useful in forming the porous polymeric intermediates of the present invention. show. Solid blocks of this intermediate were formed for all of the exemplified formulations, and thin films of the intermediate were also formed using the above process when indicated in the table. As shown in the table below, many of the intermediate compositions are used and involve the use of a suitable solvent to extract the compatible liquid from the intermediate composition and subsequent removal of said solvent, e.g. by evaporation. In particular, a microporous polymer of the present invention was formed. As shown in the table below, many of the compatible liquids exemplified in the Examples below are functional liquids that are useful not only as compatible liquids, but also as flame retardants, slip agents, and the like. Thus, intermediate compositions formed with this functional liquid are useful as solid polymer additives, etc., as well as intermediates in the formation of porous polymers. The functional liquids appearing in the examples below are identified as such by the presentation of one or more of the following symbols under the column "Type of functional liquid":
AF (antifoggant); AO (antioxidant); AR (animal repellent); FA (fuel additive); FG (fragrance); FR (flame retardant); IR (insect repellent); L (lubricant) agent); M (medicine); MR (insect repellent); OR (deodorant); P
(plasticizer); PA (abrasive); PE (insecticide); PF (fragrance); S (slip agent); SF (surfactant) and ST
(Stabilizer). Examples 1 to 27 Examples 1 to 27 of the Table are prepared using standard manufacturing methods from high density polyethylene (“HDPE”) and compatible liquids found to be useful.
The formation of a homogeneous porous polymeric intermediate is shown in the form of a cylindrical block having a radius of inches and a depth of about 2 inches. This high density polyethylene is 0.3g/10
Plaskon AA55-003 with a melt index of 100 min and a density of 0.954 g/cc
Supplied by Allied Chemical under the trade name (trade name). Many of the illustrated intermediates were extracted to form porous polymers as shown in the table. The manufacturing details and types of functionally useful liquids are given in the table:

[Table] Phenyl

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

[Table] (1) Akzochemy's product name for styrenated bound phenols

[Table] (1) Styrenated bound phenols from Akzo Chemie.
A second photomicrograph of the porosity of Examples 38 and 122
8 and 29 are shown, respectively. The 2000x magnification photomicrograph shows cellular structures with a significant amount of "lobes" that were uniformly present throughout the sample. Examples 189 to 193 Examples 190 to 194 in the table inject solutions into glass dishes to form cylindrical blocks having a radius of about 1.75 inches and a depth of about 0.25 inches, except for standard demonstrates the formation of a homogeneous porous polymeric intermediate by forming it from a "noryl" polymer and a compatible liquid that has been found to be useful. If this instruction is given,
Microporous polymers were similarly prepared. The manufacturing details and types of functionally useful liquids are given in the table:

【table】

[Table] The micrograph of the microporous polymer of Example 192 is shown in the second table.
It is shown in Figure 5. A 2500x micrograph shows microcellular structures with spherical resin deposits on the cell walls. Examples 194-236 In the table, Examples 194-236 were prepared using standard manufacturing processes from polypropylene ("PP") and compatible liquids found to be useful, with a radius of about 1.25 inches and about 0.5 The formation of a homogeneous porous polymeric intermediate is shown in the form of cylindrical blocks having a depth of inches. Additionally, in the examples shown, blocks and/or thin films were made that were approximately 6 inches deep. Also as shown, microporous polymers were prepared. The manufacturing details and types of functionally useful liquids are listed in the table:

【table】

【table】

【table】

[Table] The micrograph of the porous polymer of Example 225 is shown in the second table.
As shown in FIGS. The micrographs of Figures 2 and 3 at 55x and 550x respectively show the fine cellular structure and interconnecting pores of the polymer. Examples 237 to 243 Examples 237 to 243 of the Table are made using standard manufacturing processes from polyvinyl chloride (“PVC”) and compatible liquids found to be useful.
The formation of a homogeneous porous polymeric intermediate is shown in the form of a cylindrical block having a radius of 1 inch and a depth of about 0.5 inch. Many of the illustrated intermediates are extracted to form porous polymers as shown in the table. The manufacturing details and types of functionally useful liquids are listed in the table:

【table】

[Table] The micrograph of the porous polymer of Example 242 is shown in the second table.
It is shown in Figure 7. The 2000x micrograph shows this in contrast to the cellular structures shown by Figures 7, 13, 18, 20, and 24, where the cell size is larger and more easily observed at comparable magnification. Figure 2 shows the extremely small cell size of microporous polymers. This photomicrograph also shows the presence of large amounts of resin masking the elementary cellular structures. Examples 244 to 255 Examples 244 to 255 of the Table are prepared using standard manufacturing processes from methylpentene (“MPP”) and compatible liquids found to be useful.
The formation of a homogeneous porous polymeric intermediate is shown in the form of a cylindrical block having a radius of 1 inch and a depth of about 2.0 inches. Many of the illustrated intermediates were extracted to form porous polymers as shown in the table. The manufacturing details and types of functionally useful liquids are given in the table:

【table】

【table】

[Table] * This liquid was extracted from a solid.
A second photomicrograph of the porous polymer of Example 253
This is shown in Figure 2. The 2400x micrograph shows a highly flattened cell wall, comparable to the structure observed in Figure 14. Examples 256 to 266 Examples 256 to 266 of Table The formation of a homogeneous porous polymeric intermediate is shown in the form of a cylindrical block with a depth of .
All of the illustrated intermediates are extracted to form porous polymers. Manufacturing details and types of functionally useful liquids are given in Table XI.

【table】

[Table] The micrograph of the microporous polymer of Example 260 is shown in the second table.
It is shown in Figure 6. Although this cell is small compared to the cells shown in Figures 4, 7, 13, 18, and 25, there is an elementary microcellular structure. Example 267 This example uses a standard manufacturing process and
The formation of a homogeneous porous intermediate from 30% high impact polystyrene (1) and 70% hexabromobiphenyl is shown upon heating to 280°C. The polymeric intermediate thus formed is about 2.5 inches in diameter and about 0.5 inches deep. Hexabromobiphenyl is useful as a flame retardant and the porous intermediate is useful as a solid flame retardant additive. Example 268 This example uses a standard manufacturing process and
Figure 2 shows the formation of a homogeneous porous polymer intermediate from 25% acrylonitrile-butadiene-styrene terpolymer (2) and 75% diphenylamine upon heating to 220<0>C. The polymer intermediate thus formed was about 2.5 inches in diameter and about 2 inches deep.
A microporous polymer was formed by extracting diphenylamine. This diphenylamine is useful as a disinfectant and antioxidant and the porous intermediate has the same utility. (1) Union Coverbide "Bakelite" polystyrene was used for injection molding with the following properties: Tensile strength (1/8 inch thickness)
5000psi; final elongation (1/8 inch thickness) 25psi;
Tensile modulus (1/8 inch thickness) 380000psi;
Rockwell hardness (1/4 x 1/2 x 5 inches) 90;
Specific gravity, natural, 1.04. (2) Uniroyal's Clarastic ABS polymer was used with the following properties: specific gravity 1.07; impact strength (1/8 inch bar sample), 73 mm, 1.3-1.9 ft-lb/inch notch. ; Tensile strength 8800psi; and Rockwell hardness, 118R. Examples 269 and 270 15 using standard manufacturing methods and heated to 220°C
25 supplied by Dow, which has a melt viscosity of poise and a crystallinity of 8% and contains 36% chlorine.
% chlorinated polyethylene thermoplastic, and 75%
% N,N-bis(2-hydroxyethyl)tallow-amine (Example 270), and a homogeneous porous polymer intermediate from 75% chlorinated polyethylene thermoplastic and 25% 1-dodecanol (Example 271). formed a body. This porous polymeric intermediate has a diameter of approximately
It was 2.5 inches long and about 2 inches deep. Example 271 Using a standard manufacturing process from 25% chlorinated polyethylene elastomer and 75% diphenyl ether as used in Example 271 and
C. to form a homogeneous porous polymer intermediate. This porous polymeric intermediate was approximately 2.5 inches in diameter and 2 inches deep. Diphenyl ethers are useful as perfumes and the intermediates are also useful as perfumes. Examples 272-275 Examples 272-275 of Table
The formation of a homogeneous porous polymeric intermediate in the form of a cylindrical block having a radius of about 1.25 inches and a depth of about 0.5 inches from rubber (1) and a compatible liquid that has been found to be useful is illustrated. A thin film was also formed outside the cylindrical block as shown. Manufacturing details and functionally useful liquid types
Listed in Table XII. (1) A Kraton SBR polymer from Siel Chemical Co., Ltd. with the following properties was used: Tensile strength, 3100
-4600 psi; elongation at break; 880-1300 and Rockwell hardness, 35-70 Shore A.

[Table] * This liquid was extracted from a solid.
Examples 276 to 278 Examples 277 to 279 of the table were prepared using standard manufacturing processes from "Surlyn" (1) and compatible liquids found to be useful, with a radius of 1.25 inches and approximately 0.5 inches. Figure 1 shows the formation of a homogeneous porous polymeric intermediate in the form of cylindrical blocks with a depth of .
In addition to the cylindrical block shown, a thin film was also formed. Extracting two of the illustrated intermediates,
A porous polymer as shown in the table was formed. Manufacturing details and types of functionally useful liquids are set forth in the table: (1) DuPont "Surlyn" ionomer resin 1652, lot number 115478, having the following properties: density 0.939 g/cc. ; Melt flow index, 4.4 decigrams/min; Tensile strength 2850 psi; Yield strength 1870 psi; Elongation 580%

[Table] * This liquid was extracted from a solid.
A second photomicrograph of the porous polymer of Example 277
3 and 24. Figure 23 at 255x shows a polymeric microcellular structure with few "lobes" and a relatively thick cell wall compared to, for example, Figure 25. Example 279 A homogeneous porous polymeric intermediate is formed from equal parts high density polyethylene-chlorinated polyethylene blend and 75% 1-dodecanol using standard manufacturing processes and heated to 200°C. Ta. About 20 or so
The porous polymer intermediate was cast into a film having a thickness of 25 mils. HDPE and CPE from the previous example were used. Example 280 A homogeneous porous polymeric intermediate was formed from equal parts of a high density polyethylene-polyvinyl chloride blend and 75% 1-dodecanol using a standard manufacturing process and heated to 200°C. . The intermediate body thus formed was about 2 inches deep and about 2.5 inches in diameter. HDPE and PVC from the previous example were used. Example 281 A homogeneous porous polymer intermediate is prepared from equal parts of a high density polyethylene/acrylonitrile-butadiene-styrene terpolymer blend and 75% 1-dodecanol using standard manufacturing processes and heated to 200°C. formed a body. The intermediate body thus formed was about 2 inches deep and about 2.5 inches in diameter. HDPE and ABS from the previous example were used. Examples 282 to 285 Examples 282 to 285 of the Table are prepared using standard manufacturing processes from equal parts of low density polyethylene/chlorinated polyethylene blends and compatible liquids found to be useful. radius and about 2
The formation of a homogeneous porous polymeric intermediate is shown in the form of cylindrical blocks having a depth of inches. Example 283
In this case, the method described above was used, but this intermediate was formed into a film having a thickness of about 20 to 25 mils. LDPE and CPE were those used in the previous example. The manufacturing details and types of functionally useful liquids are listed in the table:

[Table] Examples 286 and 287 Using the standard manufacturing process, and in Example 286
220°C, and in Example 288 to 270°C,
Equal parts low density polyethylene/polypropylene blend and 75% N,N-bis(2-hydroxyethyl)talo-amine (Example 286) and equal parts low density polyethylene/polypropylene blend and 50%
A homogeneous porous polymeric intermediate was formed from % N,N-bis(2-hydroxyethyl)tallow-amine (Example 287). Both porous polymer intermediates were about 25 inches in diameter and about 2 inches deep. LDPE and PP from the previous example were used. Example 288 Using standard manufacturing processes and heating to 200°C,
A homogeneous porous polymer intermediate was formed from 50% N,N-bis(2-hydroxyethyl)talo-amine and 50% polypropylene/polystyrene blend (25 parts polypropylene). This porous polymeric intermediate was about 2.5 inches in diameter and about 2 inches deep. The previous examples PP and PS were used. Example 289 Using standard manufacturing processes and heating to 200°C,
A homogeneous porous polymeric intermediate was formed from 75% 1-dodecanol and equal parts polypropylene/chlorinated polyethylene blend. This porous polymeric intermediate was about 25 inches in diameter and about 0.5 inches deep. The PP and CPE of the previous example were used. Examples 290-300 Examples 290-300 are polymer-compatible liquids useful for the formation of homogeneous porous polymer intermediates from high density polyethylene and N,N-bis(2-hydroxyethyl)tallow-amine. The concentration range is illustrated.
In each instance, the intermediate was approximately 2 inches deep and approximately 2.5 inches in diameter. HDPE was used in the previous example. Manufacturing details and observed physical properties are listed in the table:

[Table] 2000 micrographs of the porous polymer of Example 300
It is shown in FIG. 19 at a magnification. This cell is not clearly visible at this magnification. Figure 19 can be compared to Figure 17 at a similar polymer concentration of 70% cell size, which is much smaller by a factor of 2475. Examples 301 to 311 These examples are made of low density polyethylene and N,
Figure 2 shows useful polymer-compatible liquid concentration ranges for the formation of homogeneous porous polymer intermediates from N-bis(2-hydroxyethyl)tallow-amine. In each example, the intermediate was about 0.5 inches deep and about 2.5 inches in diameter. LPDE was that used in the previous example. Manufacturing details and observed physical properties are listed in the table:

【table】

[Table] Micrographs of the porous polymers of Examples 303, 307, and 310 are shown in Figures 14-15 (250x and 2500x, respectively).
They are shown in FIG. 16 (2500 times) and FIG. 17 (2475 times), respectively. This drawing shows that with increasing polymer content,
The cell size is shown decreasing from very large (Figure 15, 20% polymer) to very small (Figure 17, 70% polymer). The relatively flat cell walls of the 20% polymer in Example 303 are similar to the methylpentene polymer (secondary
2) and can be observed in FIG. FIG. 15 is an enlarged view showing a part of the cell wall shown in FIG. 14. The microcellular structure of the porous polymer can be observed in FIG. Examples 312-316 Examples 312-316 illustrate useful polymer-compatible liquid concentration ranges for the formation of homogeneous porous polymer intermediates from low density polyethylene and diphenyl ether. In each instance, the intermediate was approximately 0.5 inches deep and approximately 2.5 inches in diameter. LDPE was that used in the previous example. Manufacturing details and observed physical properties are listed in the table:

TABLE Examples 317-321 Examples 317-321 illustrate useful polymer-compatible liquid concentration ranges for the formation of homogeneous porous polymer intermediates from low density polyethylene and 1-hexadecene. In each case, the intermediate was about 2 inches deep and about 2.5 inches in diameter. LDPE was that used in the previous example. Manufacturing details and observed physical properties are listed in the table:

[Table] Examples 322 to 334 These examples are polypropylene and N,N-
1 illustrates a useful polymer-liquid concentration range for the formation of a homogeneous porous polymer intermediate from bis(2-hydroxyethyl)tallow-amine. In each case, the intermediate was approximately 0.5 inches deep and 2.5 inches in diameter. I also made a film as shown. PP was that used in the previous example. Manufacturing details and observed physical properties are listed in the table:

[Table] Examples 322, 326, 328, 330 and 333 are the sixth
or shown in Figure 10 (each 1325 times, 1550
1620x, 1450x and 1250x). An extreme leaf of the 10% microporous polymer is shown in Figure 6, but still retains the microcellular structure. These figures show decreasing cell size as the amount of polymer increases. However, despite the small cell size, microcellular structures are present in each case. Examples 335-337 This example illustrates a useful polymer-compatible liquid concentration range for the formation of homogeneous porous polymer intermediates from polypropylene and diphenyl ether. In each case, the intermediate was about 0.5 inches deep and about 2.5 inches in diameter. Furthermore, as shown, a thin film was also made. PP was that used in the previous example. Manufacturing details and observed physical properties are listed in the table:

[Table] Micrographs of the porous polymers of Examples 335, 336, and 337 are shown in Figure 11 (2000x magnification) and Figure 12 (2059x magnification).
(1950x) and Figure 13 (1950x). The accompanying figures show that the pore size decreases as the polymer increases, with Figure 11 showing smooth cell walls, while Figures 12 and 13 show cells and communicating pores. Microcellular structures are present in each of the figures. Examples 338 to 346 These examples are based on styrene-butadiene rubber and N,N-bis(2-hydroxyethyl)tallow.
Figure 2 shows useful polymer-compatible liquid concentration ranges for the formation of homogeneous porous polymer intermediates from amines. In each instance, the intermediate was approximately 0.5 inches deep and 2.5 inches in diameter. Additionally, a thin film was made as shown. SBR was that used in the previous example. Manufacture details and permissible physical characteristics in Section XI
In the table:

【table】

[Table] Microscopic photographs of the styrene-butadiene rubber microporous polymers of Examples 339 and 340 are shown in FIG. 20 (2550 times) and FIG. 21 (2575 times). This figure shows a microcellular structure of a microporous polymer. Figure 21 also shows the presence of globular polymeric deposits on the cell walls. Examples 347-352 Examples 347-352 illustrate useful polymer-compatible liquid concentration ranges for the formation of homogeneous porous polymer intermediates from styrene-butadiene rubber and decanol. In each example, the intermediate was approximately 0.5 inches deep and 2.5 inches in diameter. Additionally, thin films were made as shown. SBR was that used in the previous example. Manufacturing details and observed physical properties are given in Table XII:

TABLE Examples 353-356 These examples illustrate useful polymer-compatible liquid concentration ranges for the formation of homogeneous porous polymer intermediates from styrene-butadiene rubber and diphenylamine. In each example, the intermediate was about 0.5 inches deep and about 2.5 inches in diameter.
Manufacturing details and observed physical properties are listed in the table:

Table: Examples 357 to 361 Examples 357 to 361 demonstrate the formation of homogeneous porous polymeric intermediates from "Surlyn" resin and N,N-bis(hydroxyethyl)talo-amine as used in the previous examples. Examples of useful polymer-compatible liquid concentration ranges for In each example the intermediate is at a depth of approximately
It was 0.5 inches and 2.5 inches in diameter. Additionally, thin films were made as shown. Manufacturing details and observed physical properties are listed in the table:

EXAMPLES 362-370 These examples demonstrate polymer-compatibility useful for the formation of homogeneous porous polymer intermediates from "Surlyn" resins and diphenyl ethers as used in the previous examples. Illustrating liquid concentration ranges. In each case, the intermediate was about 0.5 inches deep and about 2.5 inches in diameter. As further shown, thin films were made. Manufacturing details and observed physical properties are listed in the table:

【table】

Table: Examples 371-379 Examples 371-379 demonstrate polymer-compatibility useful for the formation of homogeneous porous polymer intermediates from "Surlyn" resin and dibutyl phthalate as used in the previous examples. Indicates liquid concentration range. In each example,
This intermediate was about 0.5 inch deep and about 0.5 inch in diameter. Manufacturing details and observed physical properties are listed in the table:

Table: Prior Art Reference Examples 380-384 Reference Examples 380-384 Reference Examples 380-384 are reproductions of various prior art compositions shown to have physical structures different from those of the present invention. Reference Example 380 Sodium bis(2-ethylhexyl) to obtain a product with some physical integrity
A porous polymer was prepared according to the method of Example 1 of US Pat. No. 3,378,507 with a modification using soap as the water-soluble anionic surfactant in place of sulfosuccinate. In a Brabender Plasticorder internal heated blender, combine approximately 350 parts by weight of Exxon Chemical Co. LD606 type polyethylene 33 1/2 parts and Ivor Soap Flake 66 2/3 parts until a homogeneous blend is formed.
Mixed at a machine temperature of 0. This material was compression molded in a rubber mold with a 2.5 inch by 2.5 inch cavity 20 mils deep at a temperature of approximately 350 mm and a pressure of 36,000 pounds per square inch. The resulting samples were washed in a slow running stream of tap water for about 3 consecutive days and then subsequently washed by immersion in eight distilled water baths for about 1 hour each. The resulting sample also contained some soap and had poor handling properties. Figures 47 and 48 are micrographs of the product of Reference Example 380 at 195x and 2000x, respectively. The product appears to be a relatively non-uniform polymeric structure with no defined cellular cavities or interconnecting pores. Reference Example 381 A porous polymer was produced according to the method of Example 2, Sample D of US Pat. No. 3,378,507, with modifications to obtain a sample with some handling strength. Seventy-five parts of Ivory soap flakes and Exxon Chemical Co. LD606 polyethylene were mixed in a Brabender Plasticorder internal heated blender at a machine temperature of about 350° and a sample temperature of about 330° until a homogeneous blend was formed. Then one with a mold cavity diameter of 2 inches and a depth of 20 mils.
This material was injection molded on an Ons Watson-Stillman injection molding machine. The resulting samples were washed in a slow running stream of tap water for about 3 consecutive days and then by immersion in eight distilled water baths for about 1 hour each. The resulting sample still retained some soap. Figures 45 and 46 are micrographs of the product of Example 381 at 240x and 2400x, respectively. The product of this example does not have the typical cell-like structures of the present invention, as is clear from the photomicrograph. Reference Example 382 A porous polymer was prepared according to the method of Example 3, Sample A of US Pat. No. 3,378,507. In a Brabender Plasticorder internal heated blender, 25 parts of Novamont F300 8N19 type polypropylene and 75 parts of Ivory Soap Flake were mixed at a machine temperature of approximately 330°C until a homogeneous blend was formed. This material was then compression molded in a rubber mold. The resulting sample was found to have little strength. A portion of the resulting sample was washed in a slow running stream of tap water for about 3 consecutive days and then subsequently washed by immersion in eight distilled water baths for about 1 hour each. This washed product was found to have very poor handling properties. Figures 51 and 52 are micrographs of the product of Reference Example 382 at 206x and 2000x, respectively. This photomicrograph shows that the product does not have cellular structures according to the invention. Reference Example 383 The process of Example 3, Sample A of US Pat. No. 3,378,507 was modified to obtain a product with improved handling strength. Bolling's open 2 roll rubber mill.
Novamont Inc. until a homogeneous mixture is formed.
25 parts of F300 8N19 type polypropylene and 75 parts of Ivory soap flakes were mixed for about 10 minutes at a temperature of 350°C. This material was molded into a 1 oz. Watson mold with a 2 inch mold cavity diameter and a 20 mil depth.
Injection molded using a Stillman injection molding machine. The resulting samples were washed in a slow running stream of tap water for about 3 consecutive days and then by immersion in eight distilled water baths for about 1 hour each. The resulting sample still retained some soap. The resulting product was found to be stronger than that of Reference Example 382. Figures 49 and 50 are micrographs of the product of Reference Example 383 at 195x and 2000x, respectively. The irregular shape shown by this photomicrograph is easily distinguishable from the structure of the present invention. Reference example 384 Modified to obtain a more homogeneous mixture of materials,
A porous polymer was prepared according to the examples of US Pat. No. 3,310,505. In a Brabender Plasticoder internal heat blender, blend 40 parts Exxon Chemical Co. LD606 polypropylene and Rohm & Hass Co. polymethyl methacrylate 60 parts until a homogeneous blend is formed.
The parts were mixed for about 10 minutes at a machine temperature of about 350°C. This material was then cold milled into sheets and subsequently compression molded using a heated 4 inch annular die with a depth of 20 mils and 30 tons of pressure for approximately 10 minutes. The resulting composition was extracted with acetone in a large Soxhlet extractor for 48 hours. Figures 53 and 54 are micrographs of the product of Reference Example 384 at 205x and 2000x, respectively. The heterogeneous structure shown by this photomicrograph is easily distinguishable from the homogeneous structure of the present invention. Physical Properties of Examples 225 and 358 To gain a quantitative understanding of the homogeneous structures of the present invention,
Several samples of microporous materials and certain prior art samples were analyzed with an Aminco mercury immersion porosimeter. Figures 30 and 31 show 25% polypropylene and
Figure 32 is the mercury infiltration curve of a half-inch block of Example 225 made with 75% N,N-bis(2-hydroxyethyl)tallowamine, and Figure 32 is the mercury intrusion curve of a 6-inch block of Example 225. It is a curve. All mercury infiltration curves are shown in semi-log graphs with respect to the equivalent pore size shown in log scale on the abscissa. Figures 30-32 show typical narrow distributions of pore sizes for compositions of the present invention. . The half-inch sample of Example 225 was determined to have about 76% void space and an average pore size of about 0.5 microns, and the 6-inch block was determined to have about 72% void space and an average pore size of about 0.6 microns. Ta. Figure 33 is a mercury penetration curve for the product of Example 358 made with 40% polypropylene and 60% N,N-bis(2-hydroxyethyl)talo-amine. Figure 33 shows that this sample has a typical narrow pore size distribution. This sample was determined to have approximately 60% void space and an average pore size of approximately 0.15 microns. It is readily apparent that the compositions of the present invention have a pore size distribution such that at least 80% of the pores present in the composition fall within more than 10 of the transverse points of the mercury infiltration curve. The pore size distribution of this composition is therefore characterized as "narrow". Physical Properties of Prior Art Commercial Compositions Reference Example 385 The composition of this example was commercially available Celgard 3501 (trade name) microporous polypropylene manufactured by Celanese.
Figure 34 is a mercury infiltration curve for a sample showing a large population of pores in the 70 to 0.3 micron range. This sample was determined to have about 35% void space and an average pore size of about 0.15 microns. Reference Example 386 The composition of this example is commercially available A-20 microporous polyvinyl chloride manufactured by Amerase. Figure 35 is the mercury infiltration curve for this sample and shows a very broad pore size distribution. This sample was determined to have about 75% void space and an average pore size of about 0.16 microns. Reference Example 387 The composition of this example is commercially available A-30 microporous polyvinyl chloride manufactured by Amerase. Figure 36 is the mercury infiltration curve for this sample and shows a very broad pore size distribution. This sample was determined to have approximately 80% void space and an average pore size of approximately 0.12 microns. Reference Example 388 The composition of this example is commercially available Porex microporous polypropylene. Figure 37 is a mercury infiltration curve for a sample showing a very wide distribution of very small cells as well as a distribution of very large cells. This sample is approximately
It was determined to have 12% void space and an average pore size of approximately 1 micron. Reference Example 389 The composition of this example is commercially available Millipore BDWP29300 microporous polyvinyl chloride. FIG. 38 is a mercury infiltration curve for a sample showing a relatively narrow distribution in the 0.5 to 2 micron range, as well as a large number of cells smaller than about 0.5. This sample was determined to have about 72% void space and an average pore size of about 1.5 microns. Reference Example 390 The composition of this example is commercially available Metricel TCM-200 microporous cellulose triacetate manufactured by GELMAN. Figure 39 is a mercury infiltration curve for a sample showing a wide pore size distribution down to about 0.1 micron. This sample was determined to have about 82% void space and an average pore size of about 0.2 microns. Reference Example 391 The composition of this example is a commercially available Acropore WA microporous acrylonitrile manufactured by Gelman.
It is a polyvinyl chloride copolymer. FIG. 40 is a mercury infiltration curve for a sample showing a wide pore size distribution. This sample was determined to have about 64% void space and an average pore size of about 1.5 microns. Physical Properties of Prior Art Reference Examples 380-384 The products of Prior Art Reference Examples 380-384 were analyzed by mercury infiltration. Figures 41-43 are mercury infiltration curves showing the broad pore size distribution of the products of Reference Examples 381, 380 and 383, respectively. Figure 44 is a mercury infiltration curve for the product of Example 384, which shows a large number of very small pore sizes and a population of pore sizes in the 45-80 micron range. Reference example 380,
The products of 381, 383 and 384 are approximately 54%, 46%,
They were determined to have 54% and 29% void space and average pore sizes of approximately 0.8 microns, 1.1 microns, 0.56 microns and 70 microns, respectively. Examples 392-399 These examples demonstrate useful polymer/compatible liquid concentrations for the formation of homogeneous porous polymer intermediates from polymethyl methacrylate and 1,4-butanediol using standard manufacturing processes. Illustrate the range.
The intermediate formed in each example was approximately 0.5 inches deep and approximately 2.5 inches deep. This polymethyl methacrylate is Plexiglas acrylic plastic molding powder (trade name).
Supplied by Rohm and Hass as lot number 386491. The details of the production are listed in the table: Table Example No. Liquid % Temperature °C 392 90 215 393 85 225 394 80 225 395 70 210 396 60 229 397 50 230 398 40 229 399 30 225 1,4-Butanediol was removed from the product of Example 395 and the resulting structure was determined to be the cellular structure of the present invention, as seen in Figure 61, which shows the microporous product at 5000x magnification. Example
Same polymer/liquid system as that of 394 per minute
Cooling was performed at a rate below 4000° C. and still produced the cellular structures of the present invention. Example 400 Using a standard manufacturing process and as used in the previous example, 30% polymethyl methacrylate and
A porous polymer intermediate was prepared by heating 70% lauric acid to 175°C and cooling to form a porous polymer intermediate. Lauric acid was removed from the resulting intermediate to form the microporous cellular structure of the present invention. Example 401 30% nylon 11 and
A porous polymer intermediate was prepared by heating 70% ethylene carbonate to a temperature of 218°C and then cooling the resulting solution to form a porous polymer intermediate. The ethylene carbonate was removed from the intermediate and the resulting microporous polymer was determined to have the cellular structure of the present invention. Example 402 Using a standard manufacturing process and using 30% nylon 11 and 70% 1,2 as used in the previous examples
- Propylene carbonate was heated to produce a porous polymer intermediate. The 1,2-propylene carbonate intermediate was removed and the resulting microporous polymer was determined to have the cellular structure of the present invention. Examples 403-422 Examples 403-422 contain varying amounts of nylon 11 and tetramethylene sulfone supplied by Shell as Sulfone W (trade name), as used in the previous examples, and contain approximately 2.5 Figure 2 illustrates the formation of a porous polymer intermediate from a polymer/liquid system containing % water. Cooling the various concentrates at various concentrations and from various solution temperatures as shown in Table 1, this also causes increased cooling rates and increased concentrations of polymer to generally produce a decrease in cell size. .

【table】

TABLE The above table also shows that for systems cooled at 20° C. per minute at liquid concentrations of 40 to 10%, there is no visible porosity as a result. This result is fully expected as seen with respect to Figure 62, which shows melting curves for a range of nylon 11/tetramethylene sulfone concentrations, as well as crystallization curves at various rates of cooling. From Figure 62 it can be seen that at a cooling rate of 20°C/min, the system containing 40% liquid does not fall within the substantially flat part of the crystallization curve and therefore does not form the desired microporous structure. It is clear that this is expected. Figure 63 is an example
Examples showing representative cell-like structures of 403-418
This is a 2000x microscopic photo. Example 423 30% polycarbonate and 70% polycarbonate using standard manufacturing processes and supplied by General Electric under the trade name Lexan.
A porous polymer intermediate was prepared by heating menthol to a temperature of 206°C and cooling to form a porous polymer intermediate. The menthol was extracted and a cellular microporous structure was formed as shown in Figure 64, which is a micrograph of the product of this example at 2000x magnification. Example 424 This example uses poly-2,6-dimethyl-1,4, commonly referred to as polyphenylene oxide, supplied by Scientific Polymer Products.
- illustrates the formation of microporous cellular structures of the present invention from phenylene oxide. The homogeneous microporous polymer intermediate was prepared by combining 30% of the above polyphenylene oxide and 70% of N,N-bis(2) heated to a temperature of 275°C.
-hydroxyethyl)tallow-amine,
This intermediate was then formed using standard manufacturing processes. This liquid is removed from the intermediate and
No. 65 is a micrograph of the product of this example at 2000x magnification.
As can be seen, a cellular structure of the invention was produced. Example 425 This example demonstrates the formation of a non-cellular product of the invention by cooling a homogeneous solution of 40% polypropylene and 60% dibutyl phthalate, as used in the previous example. This solution was extruded onto a chilled belt approximately 10 mils thick, and the cooling rate was 2400 mils.
It was over ℃. A quantity of dispersion sol was applied to the surface of the belt at a location before the solution was extruded. This liquid was removed from the resulting film and a non-cellular microporous product was formed as seen in Figure 65, which is a photomicrograph of the product of this example at 2000x magnification. Example 426 This example uses a method identical to that of Example 425, with 25% polypropylene and
Figure 2 illustrates the formation of a non-cellular product of the invention by cooling a homogeneous solution of 75% N,N-bis(2-hydroxyethyl)tallow-amine. This liquid was removed from the resulting film and a non-cellular microporous product was formed as seen in Figure 67, which is a photomicrograph of the product of this example at 2000x magnification. The products of Examples 425 and 426 were analyzed by mercury infiltration porosity measurements, and the respective infiltration curves are shown in FIGS. 68 and 69. Although both products have generally narrow pore size distributions, it is clear that Example 426 exhibits a narrower distribution than the product of Example 425. Thus, the product of Example 425 has a calculated S value of 24.4, while the product of Example 426 has a calculated S value of only 8.8. However, the average pore size of Example 425 is much smaller, 0.096 microns, whereas the average pore size of the product of Example 426 is 0.589. In order to quantitatively illustrate the unique properties of the cellular compositions of the present invention, a number of microporous products were prepared according to standard manufacturing processes and details related thereto are presented in Examples 427-457. To summarize. The products of this example are analyzed by mercury immersion porosimetry to determine their average pore diameter and S value, and by scanning electron microscopy to determine their average cell size, S.
The results of this analysis are shown in Table 1.

[Table]

[Table] Nate

【table】

【table】

【table】

【table】

[Table] The data contained in Tables XII are summarized in Figure 70, which shows logS/C versus logC/
This is a plot of P. FIG. 70 shows that the cellular structure of the present invention has a logC/P of about 0.2 to about 2.4 and a logC/P of about -
is defined as having a logS/C of 1.4 to about 1.0, and more typically the polymer has a logS/C of about 0.6
logC/P of from about 2.2 to about -0.6 to about 0.4
It is clear that it has logS/C. Thus, as can be seen, the present invention provides a facile method for making microporous polymers from synthetic thermoplastic polymers of widely varying thicknesses and shapes. This microporous polymer has a unique microcellular structure and is characterized by pore diameters with a relatively narrow size distribution anyway. The first step is to select a liquid that is compatible with the polymer, i.e., forms a homogeneous solution with the polymer and can be removed from the polymer after cooling, and to ensure that the desired microporous polymer structure results. These structures are formed by cooling the solution in a specific manner. As can also be seen, the present invention also provides microporous polymeric products that contain relatively large amounts of functionally useful liquids, such as polymeric additives, and that behave as solids. These products can be beneficially used in a variety of applications, such as masterbatching.

[Brief explanation of drawings]

FIG. 1 is a graph of temperature versus concentration for a hypothetical polymer-liquid system, showing binodial and spinodal curves and illustrating the concentration necessary to achieve a microporous polymer and practice the method of the invention. Figure 1A is a temperature versus concentration graph similar to that of Figure 1, but also includes a freezing point depression phase line;
Figure 2 is a 55x photomicrograph showing the macrostructure of the polypropylene microporous polymer of the present invention with a void volume of about 75%, and Figures 3 to 5 are 550x, 2200x and 220x, respectively. Figure 2 is a micrograph of the microporous polypropylene structure of Figure 2 at 5500x; Figures 6 through 10 are further magnifications of the microporous polypropylene structure at 1325x, 1550x, 1620x, 1450x, and 1250x, respectively; Figures 11 to 13 are micrographs of the structure in which the void space is reduced from 90% to 70%, 60%, 40% and 20%, respectively; 12 and 1 are micrographs of the microporous polypropylene structure of the invention at 2000x, 2050x, and 1950x, respectively, and the polypropylene content varies from the 10% by weight level of FIG.
Figure 3 shows the cell size decreasing as the microporous low density polyethylene structure of the present invention is increased by 20% and 30%, respectively; 14 and 15 show the macro- and microstructure of a microporous polymer containing 20% by weight polyethylene, and FIGS. 16 and 1
Figure 7 shows microstructures having 40% and 70% polyethylene, respectively; Figures 18 and 19 respectively show microporous high density polyethylene structures of the present invention.
2100x and 2000x micrographs and respectively
Figures 20 and 21 show structures of 30% and 70% polyethylene, respectively;
Figure 22 is a 2550x and 2575x photomicrograph of an SBR polymer and shows a homogeneous cellular structure; Figure 22 is a 2400x photomicrograph of a microporous methylpentene polymer; Figures 23 and 24. are 255x and 2550x micrographs of a microporous ethylene-acrylic acid copolymer, respectively; Figure 25 is a 2500x micrograph of a microporous polymer formed from a polyphenylene oxide-polystyrene blend. It is a photograph; the 26th
Figures are micrographs at 2050x magnification and illustrate a polystyrene microporous polymer; Figure 27 is a micrograph at 2000x magnification and illustrates a polyvinyl chloride microporous polymer; Figures 28 and 29 is a 2000x micrograph of a low density polyethylene microporous polymer showing partial masking of the basic structure by the "leaf" style structure; Figures 30 to 33 are microporous polypropylene structures of the present invention. Figures 34 to 40 are mercury penetration curves for "Celgard" and the narrow pore diameter distribution characteristic of the polymers of the present invention.
Polypropylene (Figure 34), “Amerase A20”
and “Amerase A30” polyvinyl chloride (Figures 35 and 36, respectively), “Porex” polypropylene (Figure 37), “Millipore BDWP29300” cellulose acetate (Figure 38), and “Gelman TCM”.
-200'' cellulose triacetate and ``Gelman Macropar WA'' acrylonitrile-polyvinyl chloride copolymer (Figures 39 and 40, respectively) are mercury intrusion curves of commercially available microporous products;
Figures 41 to 43 show polyethylene (Figure 41)
and Fig. 42) and polypropylene (Fig. 43)
Figure 4 is a mercury infiltration curve of a microporous structure made according to US Pat.
Figure 4 is a mercury infiltration curve for a polyethylene microporous material made according to US Pat. No. 3,310,505; Figures 45-46 are the mercury infiltration curves of a polyethylene microporous material made according to US Pat. No. 3,378,507 using injection molding technology. Figure 45 (240x) shows the macrostructure and Figure 46 (2400x) shows the microstructure: Figures 47-48 show Example 2 of U.S. Pat. No. 3,378,507 using compression molding technology.
Figure 47 (195) is a micrograph of a porous polyethylene product produced by reproducing the
) shows the macro structure and Figure 48 (2000
Figures 49 to 5 indicate microstructures;
Figure 0 uses injection molding technology to obtain US patent no.
Figure 49 (195x) shows the macrostructure and Figure 50 (2000x) shows the microstructure of a porous polypropylene product prepared by reproducing Example 2 of No. 3378507; Figures 51-52 are micrographs of porous polypropylene products made by reproducing Example 2 of U.S. Pat. No. 3,378,507 using compression molding techniques; Figure 51 (206x) shows the macrostructure and Figure 52 (2000x) shows the microstructure; and Figures 53-54
Figure 53 (205x magnification) shows the macrostructure and Figure 54 (200x (fold) indicates a microstructure. Figure 55 shows melting and crystallization curves for polypropylene and quinoline polymer/liquid systems. Figure 56 shows polypropylene and N,
Figure 2 shows a melting curve and some crystallization curves for the N-bis(2-hydroxyethyl)tallow-amine polymer/liquid system. Figure 57 shows melting and crystallization curves for polypropylene and dioctyl phthalate polymer/liquid systems, systems that are outside the scope of this invention. FIG. 58 shows a phase diagram for low molecular weight polyethylene and diphenyl ether polymer/liquid systems measured at cooling and heating rates of 1° C./min. Figure 59 shows several melting and crystallization curves for low molecular weight polyethylene and diphenyl ether polymer/liquid systems. Figure 60 shows the glass transition curves for low molecular weight polystyrene and 1-dodecanol polymer/liquid systems, and Figure 61 shows the 70% of the invention made from polymethyl methacrylate.
Figure 62 shows the melting and crystallization curves for the nylon 11 and tetramethylene sulfone polymer/liquid system; In addition, the 70% void microporous cellular structure of the present invention
Figure 64 is a 2000x photomicrograph of a 70% void microporous cellular structure of the present invention made from polycarbonate, and Figure 65 is a 2000x photomicrograph of a 70% void microporous cellular structure made from polycarbonate. was given,
1 is a 2000x micrograph of a 70% void microporous cellular structure of the present invention. Figures 66 and 67 are each 60% of the invention made from polypropylene.
Void and 75% void, microporous non-cellular structure
This is a 2000x magnification micrograph. Figures 68 and 69
The figures are mercury infiltration curves for 60% void and 75% void, non-cellular microporous polypropylene structures, respectively, within the scope of the present invention. FIG. 70 is a graphical representation of the unique microporous cellular structure of the present invention as compared to certain prior art compositions.

Claims (1)

[Scope of Claims] 1. An isotropic microporous polymer structure made of a synthetic thermoplastic polymer selected from the group consisting of olefin polymers, condensation polymers, oxidized polymers, and mixtures thereof, The sharpness function (S), defined as the ratio of the pressure at which 85% of the mercury penetrates to the pressure at which 15% of the mercury penetrates, as determined by analysis of the penetration curve, is between 1 and 30 and substantially throughout the structure. Uniformly distributed average diameter (C) of 1-20 microns
a large number of substantially spherical cells with a 0.05 to 1
It has a large number of non-cellular pores with an average pore diameter of microns, and adjacent cells are interconnected by pores with a smaller diameter, and the average cell diameter (C) is
The ratio of average pore diameter (P) to average pore diameter (P) is 2:1 to 200:1,
A microporous polymer structure having a logC/P value of 0.2 to 2.4 and a logS/C value of -1.4 to 1.0. 2. The microporous polymer structure according to claim 1, which has a sharpness function of 2 to 20. 3. The microporous polymer structure according to claim 1 or 2, which has a sharpness function of 1 to 10. 4. The microporous polymer structure according to claim 1 or 2, wherein the thermoplastic polymer is polypropylene.